Note LITH CODE SUB_LITH C M Y K SORT SURF_BED ROCKTYPE1 ROCKTYPE2 ROCKTYPES ZONE SUITE BELT GROUP FORMATION MEMBER ROCKCLASS AGE simplified description Cc Cc 20 20 26 0 118 bedrock quartzite phyllite "Light-gray- to tannish-gray-weathering, massive to poorly bedded vitreous quartzite" Vermont Valley Sequence and Middlebury Synclinorium Cheshire Quartzite quartzite member Sedimentary Lower Cambrian simplified description Cca Cca 15 23 42 0 120 bedrock quartzite "Brown-weathering, gray to brown argillaceous quartzite" Vermont Valley Sequence and Middlebury Synclinorium Cheshire Quartzite argillaceous quartzite member Sedimentary Lower Cambrian simplified description Ccb Ccb 15 43 62 0 119 bedrock phyllite Layers of dark-gray biotite-muscovite-quartz phyllite near top of Cc Vermont Valley Sequence and Middlebury Synclinorium Cheshire Quartzite phyllite member Sedimentary Lower Cambrian simplified description Cco Cco 57 19 9 0 336 bedrock conglomerate limestone limestone conglomerate The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Castleton Conglomerate Metasedimentary Cambrian and Neoproterozoic? Cd Cd 20 40 50 0 114 bedrock quartzite dolostone "Thin, light-gray beds of vitreous quartzite and crossbedded sandy dolostone. Unit discontinuous in southern Vermont" Vermont Valley Sequence and Middlebury Synclinorium Danby Formation Sedimentary Upper Cambrian Cdu Cdu 26 27 32 0 117 bedrock dolostone conglomerate "Dolostone, buff- and pink-mottled and massive, or light-gray, pinkish-gray-weathering, and massive to poorly bedded. Contains distinctive small pebbles and grains of well-rounded quartz, minor beds of dolostone-breccia and conglomerate occur near Rutland" Vermont Valley Sequence and Middlebury Synclinorium Dunham Dolostone Sedimentary Lower Cambrian simplified description Ceb Ceb 16 19 47 0 331 bedrock dolomitic quartzite wacke "Dull-gray, pitted, and bluish-gray dolomitic quartz wacke and quartzite distinguished by small pebbles and grains of dark-blue to black quartz, dacitic rock fragments, and abundant plagioclase" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Eagle Bridge Quartzite Metasedimentary Lower Cambrian Chh Chh 7 14 24 0 328 bedrock slate phyllite "Dark-gray to black, sooty- to rusty-weathering, splintery-fractured pyrtic slate and phyllite and interbedded bluish-gray dolomitic quartzite" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Hatch Hill Formation Metasedimentary Upper Cambrian Cls Cls 71 23 8 0 330 bedrock limestone "Thinly laminated blue-black fine grained limestone, limestone conglomerate and boudins of whitish-gray weathering blue-gray quartzite" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices West Castleton Formation limestone member Metasedimentary Middle and Lower Cambrian simplified description Cm Cm 7 25 43 0 116 bedrock sandstone dolostone "Reddish-brown, pebbly, thin- to thick-bedded sandstone, orangey-gray- and buff-weathering well-bedded dolostone, and reddish-brown-weathering dolomitic quartzite" Vermont Valley Sequence and Middlebury Synclinorium Monkton Quartzite Sedimentary Middle Cambrian Co Co 21 35 47 0 280 bedrock phyllite "Predominantly dark-gray to black, carbonaceous to highly graphitic, fine-grained sulfidic biotite-muscovite-quartz phyllite having silicic laminae" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Ottauquechee Formation Carbonaceous phyllite member Metasedimentary Cambrian Coa Coa 100 17 100 0 286 bedrock amphibolite greenstone "Dark-green plagioclase-hornblende (+/-quartz) amphibolite and rusty-pale-green, punky-weathering ankeritic chloritic greenstone" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Ottauquechee Formation Amphibolite and greenstone member Metavolcanic Cambrian Cobq Cobq 0 50 70 0 282 bedrock quartzite "Dark-bluish-gray to black, fine-grained vitreous quartzite. Beds are as thick as 30 m or are thin and interbedded black phyllite" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Ottauquechee Formation Black quartzite member Metasedimentary Cambrian Cocf Cocf 13 30 70 0 284 bedrock schist quartzite "Tan- to dark-gray-weathering, carbonaceous, medium- to coarse-grained chlorite-plagioclase-muscovite-quartz schist and interbedded tan, gray, and bluish-gray quartzite" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Ottauquechee Formation Carbonaceous albite schist member Metasedimentary Cambrian Cocq Cocq 29 23 100 0 287 bedrock quartzite "Heterogeneous unit consisting of ankeritic greenstone, ankeritic or dolomitic muscovite quartzite, bluish-gray calcareous quartzite, and pods of brecciated dolostone" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Ottauquechee Formation Carbonate-bearing quartzite member Metasedimentary Cambrian Cof Cof 19 47 87 0 283 bedrock schist granofels "Gray and grayish-green, biotite-chlorite-muscovite-albite-quartz schist or phyllite and granofels, contains coticule, locally richly garnetiferous" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Ottauquechee Formation Feldspathic schist and granofels member Metasedimentary Cambrian Com Com 12 35 55 0 281 bedrock schist Silvery-green albite-chlorite-quartzmuscovite (+/-garnet) schist characterized by coarse muscovite porphyroblasts Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Ottauquechee Formation Coarse-muscovite schist member Metasedimentary Cambrian simplified description Copw Copw 23 45 100 0 288 bedrock metawacke "Tan to gray phyllitic metawacke composed of rounded to angular grains of quartz, blue quartz, albite and traces of detrital rock fragments in a fine-grained matrix of quartz, sericite and chlorite" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Ottauquechee Formation Metawacke member Metasedimentary Cambrian Coq Coq 40 30 90 0 285 bedrock schist quartzite "Light-gray to tan, rusty-weathering, laminated sandy muscovite-plagioclase-quartz schist and tan quartzite" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Ottauquechee Formation Schist and quartzite member Metasedimentary Cambrian Cp Cp 7 19 35 0 157 bedrock slate dolostone "Black arenaceous slate with dolomite horizons, interbedded dolostone and sandstone breccia in a dolostone matrix, and massive dolostone with thin sandstone beds" Cover rocks of the Saint Albans area Parker Slate Black slate member Sedimentary Cambrian Cpc Cpc 35 45 51 0 163 bedrock conglomerate dolostone Conglomerate consisting of round clasts of orange dolostone in a black arenaceous matrix Cover rocks of the Saint Albans area Parker Slate Dark conglomerate member Sedimentary Cambrian simplified description Cpd Cpd 13 15 63 0 185 bedrock dolostone breccia "Light-gray- to beige-weathering massive dolostone and bluish-gray-weathering mottled dolostone breccia and conglomerate, passing upward into bluish-gray and buff dolostone breccia, dark gray phyllitic dolostone and limestone in upper part" Rift and drift stage Eastern flank of the Green Mountain massif and eastern domes Plymouth Formation Dolostone member Metasedimentary Cambrian Cpdo Cpdo 13 15 63 0 158 bedrock dolostone Massive beds of white to buff dolostone Cover rocks of the Saint Albans area Parker Slate Dolostone member Sedimentary Cambrian simplified description Cpfq Cpfq 0 40 100 0 186 bedrock quartzite "Thinly laminated but massive appearing, gray- and brownish-gray- to tan-weathering flaggy biotite-muscovite feldspathic quartzite and phyllitic quartzite" Rift and drift stage Eastern flank of the Green Mountain massif and eastern domes Plymouth Formation Feldspathic quartzite member Metasedimentary Cambrian Cpq Cpq 25 35 73 0 159 bedrock calcareous sandstone Thin- to thick- bedded calcareous coarse-grained sandstone Cover rocks of the Saint Albans area Parker Slate Sandstone member Sedimentary Cambrian Cps Cps 19 19 66 0 162 bedrock dolostone limestone Sandy dolostone containing limestone clasts interfingered with sandy dolostone containing dolostone clasts Cover rocks of the Saint Albans area Parker Slate Sandy dolostone member Sedimentary Cambrian Cpsc Cpsc 35 45 51 0 161 bedrock conglomerate dolostone Conglomerate with dolostone and sandstone clasts in a calcareous sandy matrix Cover rocks of the Saint Albans area Parker Slate Calcareous sandy conglomerate member Sedimentary Cambrian Cpsh Cpsh 35 45 51 0 160 bedrock conglomerate dolostone Conglomerate with dolostone and sandstone clasts in a shaly matrix Cover rocks of the Saint Albans area Parker Slate Conglomerate member Sedimentary Cambrian Cpt Cpt 8 13 20 0 72 bedrock quartzite conglomerate "Light-gray, tan and dark-gray well-bedded pebbly quartzite, crossbedded vitreous quartzite, and local conglomerate" Adirondack lowlands and Lake Champlain lowlands Beekmantown Group Potsdam Sandstone Sedimentary Upper Cambrian simplified description Csp Csp 12 23 30 0 112 bedrock dolostone marble "Steel-gray-weathering, light-gray, massive calcitic dolostone grading upward into darker, more fissile calcitic dolostone containing white quartz knots near top" Vermont Valley Sequence and Middlebury Synclinorium Clarendon Springs Formation Sedimentary Upper Cambrian simplified description Cspl Cspl 38 43 78 0 113 bedrock marble Light bluish- gray to whitish-gray calcite marble within dolostone and beneath the calcitic marbles of the overlying Shelburne Marble Vermont Valley Sequence and Middlebury Synclinorium Clarendon Springs Formation Sedimentary Upper Cambrian Cti Cti 12 24 35 0 71 bedrock dolostone quartzite "Light-gray, yellowish-gray- to buff-weathering quartzose dolostone, pebbly dolomitic quartzite, and interbedded quartzite" Adirondack lowlands and Lake Champlain lowlands Beekmantown Group Ticonderoga Formation Sedimentary Upper Cambrian Cw Cw 20 30 50 0 115 bedrock dolostone phyllite "Well-bedded dolostone weathering beige, cream, and buff, with green, red, or gray phyllite, siliceous partings, and thin beds of blue-quartz-pebble conglomerate and quartzite" Vermont Valley Sequence and Middlebury Synclinorium Winooski Dolostone Sedimentary Middle Cambrian simplified description Cwc Cwc 18 15 45 0 329 bedrock slate phyllite "Dark-gray to black, fine-grained slate and phyllite, interbedded thinly laminated bluish-black fine grained limestone, limestone conglomerate, and boudins (Cls) of whitish-gray-weathering bluish-gray quartzite" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices West Castleton Formation slate and phyllite member Metasedimentary Middle and Lower Cambrian simplified description Cwcbb Cwcbb 43 24 13 0 335 bedrock limestone conglomerate limestone conglomerate The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices West Castleton Formation Bebe Limestone Member Metasedimentary Cambrian and Neoproterozoic? simplified description Cwcnb Cwcnb 49 29 17 0 334 bedrock conglomerate limestone limestone conglomerate The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices West Castleton Formation North Brittain Conglomerate member Metasedimentary Cambrian and Neoproterozoic? Cwcu Cwcu 17 14 26 0 327 bedrock slate phyllite "Black slate and gray phyllite exposed on Woodlawn and Tinmouth Mountains in Pawlet and Tinmouth Townships, after usage of Shumaker and Thompson (1967)" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices West Castleton and Hatch Hill(?) Formations undifferentiated Metasedimentary Cambrian CZa CZa 30 19 49 0 300 bedrock schist phyllite "Lustrous, silvery-green to bluish-gray, fine- to medium-grained, white mica-chloritoid-quartz-chlorite schist and phyllite. Distinctive chlorite streaks and 1-cm rusty needles of altered kyanite are common" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Mount Abraham Formation Metasedimentary Cambrian and Neoproterozoic CZap CZap 23 23 69 0 301 bedrock schist phyllite Schist like CZa with minor garnet and magnetite porphyroblasts Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Mount Abraham Formation Metasedimentary Cambrian and Neoproterozoic simplified description CZbagn CZbagn 35 26 26 0 365 bedrock gneiss "White, light-gray- and green-banded, fine- to medium-grained, well-layered epidote-white mica-quartz-albite (+/-garnet+/-magnetite) gneiss, contains plagioclase and polycrystalline quartz porphyroblasts" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Belvidere Mountain Structural Complex Albite gneiss Metasedimentary Cambrian and Neoproterozoic simplified description CZbb CZbb 27 27 37 0 340 bedrock wacke siltstone "Pale-reddish-brown to light-gray-weathering, medium- and fine-grained, massive to thickly bedded, olive-green to gray, micaceous quartz-feldspar greywacke and siltstone, with coarse detrital muscovite, biotite and autoclastic slate chips" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Bull Formation Bomoseen Graywacke Member Metasedimentary Neoproterozoic CZbc CZbc 44 21 48 0 361 bedrock amphibolite "Dark-gray, coarse-grained amphibolite and layered amphibolite composed of barroisite, epidote, garnet, actinolite, albite, chlorite, sphene, sericite, biotite and calcite" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Belvidere Mountain Structural Complex Coarse-grained amphibolite Metavolcanic Cambrian and Neoproterozoic CZbf CZbf 57 35 41 0 362 bedrock amphibolite "Bluish-gray, fine- to medium-grained albite-hornblende-epidote-actinolite (+/-garnet) amphibolite and quartz-bearing amphibolite" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Belvidere Mountain Structural Complex Fine-grained amphibolite Metavolcanic Cambrian and Neoproterozoic CZbg CZbg 65 19 75 0 363 bedrock schist greenstone "Green, fine-grained schist composed of chlorite, actinolite, albite, and epidote with biotite, calcite, sericite, quartz, sphene, pyrite and magnetite, includes homogeneous, schistose greenstone, albitic greenstone, and massive banded greenstone" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Belvidere Mountain Structural Complex Mafic schist Metavolcanic Cambrian and Neoproterozoic simplified description CZbk CZbk 31 39 55 0 346 bedrock slate quartzite "Predominantly green, purple and purplish-red, chloritic hematitic slate and phyllite, massive to thinly bedded. Has rare thin beds of white vitreous quartzite and contains abundant chloritoid" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Biddie Knob Formation Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZbm CZbm 11 8 36 0 342 bedrock phyllite limestone "Greenish-gray to pale-lustrous-green chlorite-muscovite-quartz phyllite, and green and purple, bedded and mottled phyllite. Locally contains boudins and thin beds of limestone and pods of pinkish-gray to cream-white dolostone, and minor quartzite" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Bull Formation Mettawee slate facies Metasedimentary Neoproterozoic simplified description CZbmg CZbmg 30 20 40 0 345 bedrock wacke conglomerate "Dark-gray to greenish-gray and whitish-gray, massive chlorite-quartz wacke, pebble conglomerate and purplish-gray hematitic lithic wacke. Uniy is rich in fragmental plagioclase, phosphatic nodules, fragments of gray quartzite, and purple and green slate chips" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Bird Mountain Grit Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZbms CZbms 17 23 27 0 349 bedrock phyllite metasiltstone "Medium- to dark-gray carbonaceous phyllite, gray slate, and metasiltstone, locally containing light-gray, medium- to thick-bedded quartzite and dolomitic quartzite (CZbq)" The Taconic Allochthon Rocks of the Dorset Mountain Slice Carbonaceous phyllite and siltstone Metasedimentary Lower Cambrian and Neoproterozoic CZbp CZbp 27 24 49 0 338 bedrock slate wacke "Gray to black slate, punky-weathering calcitic wacke and mudstone, thin limestone breccia in part equivalent to West Castleton Formation" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Browns Pond Formation Metasedimentary Lower Cambrian simplified description CZbq CZbq 32 37 52 0 349.2 bedrock quartzite dolomitic quartzite "Light-gray, medium- to thick-bedded quartzite and dolomitic quartzite" The Taconic Allochthon Rocks of the Dorset Mountain Slice Carbonaceous phyllite and siltstone Metasedimentary Lower Cambrian and Neoproterozoic CZbs CZbs 17 23 24 0 364 bedrock schist greenstone "Silvery-blue, medium-grained tectonic melange composed of muscovite schist with minor amounts of chlorite, epidote, albite, and tourmaline, contains fragments and discontinuous lenses of greenstone, coarse-grained amphibolite, and talc-phyllite" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Belvidere Mountain Structural Complex Spangly schist Metasedimentary / Metavolcanic Cambrian and Neoproterozoic CZbu CZbu 33 100 40 0 360 bedrock serpentinite metadunite "Brown- to white-weathering, green, massive, moderately to fully serpentinized dunite and peridotite and schistose serpentinite, rusty-weathering, medium-grained talc-carbonate rock and quartz-carbonate (magnesite) rock" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Belvidere Mountain Structural Complex Ultramafic rocks Metavolcanic / Metaplutonic Cambrian and Neoproterozoic CZbv CZbv 16 65 56 0 348 bedrock greenstone Basaltic volcanics The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Nassua Formation Rensselaer Graywacke Member Metavolcanic Lower Cambrian and Neoproterozoic simplified description CZd CZd 48 46 55 0 121 bedrock quartzite phyllite "Heterogeneous unit consisting of rusty- to tan-weathering flaggy feldspathic quartzite, tan-weathering quartz phyllite, and feldspathic quartzite" Cover rocks of the Southern Green Mountains Dalton Formation Dalton Formation undivided Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZdb CZdb 17 31 57 0 123 bedrock phyllite quartzite "Dark-gray to gray, rusty-weathering, well-laminated tourmaline-biotite-muscovite-quartz phyllite containing thin beds of laminated quartzite. Resembles dark phyllite of the Moosalamoo Formation (CZmp), with which it is in part correlative" Cover rocks of the Southern Green Mountains Dalton Formation Dark phyllite member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZdc CZdc 61 100 0 0 128 bedrock conglomerate "Commonly tan- to yellowish-tan-weathering, coarse- to fine-grained quartz-pebble to -cobble, quartz conglomerate and schistose quartz conglomerate. Locally dark-gray biotite-muscovite-blue-quartz-pebble wacke to conglomerate. Occurs at or near base" Cover rocks of the Southern Green Mountains Dalton Formation Conglomerate member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZdfq CZdfq 8 34 70 0 124 bedrock quartzite "Light-tan to gray-weathering, massive to thin-bedded, flaggy, tourmaline-muscovite-feldspar quartzite and interbedded phyllitic quartzite" Cover rocks of the Southern Green Mountains Dalton Formation Feldspathic quartzite member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZdm CZdm 19 43 61 0 127 bedrock dolostone "Buff, sandy, massive dolostone as lens in CZdph" Cover rocks of the Southern Green Mountains Dalton Formation Dolostone member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZdph CZdph 16 19 67 0 126 bedrock phyllite quartzite "Rusty-tan to gray, thinly layered phyllite, tourmaline-biotite-muscovite-quartz phyllite, and quartzite mapped along western flank of the Green Mountain massif in the South Wallingford area" Cover rocks of the Southern Green Mountains Dalton Formation Phyllite member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZdq CZdq 16 19 67 0 122 bedrock quartzite Tan to whitish-gray vitreous quartzite and minor blue-quartz-pebble quartzite Cover rocks of the Southern Green Mountains Dalton Formation Quartzite member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZds CZds 12 27 54 0 125 bedrock schist quartzite "Dark-gray to silvery-gray, tourmaline-muscovite- biotite-quartz schist and feldspathic schist and quartzite. Similar in appearance to CZhs of the Hoosac Formation exposed to the east" Cover rocks of the Southern Green Mountains Dalton Formation Lustrous quartz schist member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZf CZf 34 33 73 0 176 bedrock schist quartzite "Silvery-green to grayish-green, medium-grained albite-chlorite-muscovite-quartz schist with white albite porphyroblasts, +/-garnet+/-magnetite" Rift and drift stage "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" Fayston Formation Albite schist member Metasedimentary Lower Cambrian and Neoproterozoic CZfa CZfa 70 13 50 0 177 bedrock greenstone amphibolite "Dark-green, pitted-weathering, foliated carbonate-albite-chlorite (+/-magnetite+/-epidote) greenstone or amphibolite" Rift and drift stage "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" Fayston Formation Greenstone member Metavolcanic Lower Cambrian and Neoproterozoic CZfb CZfb 35 32 59 0 136 bedrock phyllite dolostone "Dark-gray to sooty-black carbonaceous phyllite, interbedded dolostone boulder conglomerate to breccia, and blue- and gray-mottled sulfidic dolostone" Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Forestdale Formation Phyllite and dolostone breccia member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZfc CZfc 37 44 74 0 180 bedrock schist "Gray to medium-dark-gray, rusty weathering, carbonaceous albite-chlorite-quartz-muscovite schist, containing porphyroblasts of black albite. Unit resembles gray albitic granofels and schist of the Hoosac Formation (CZhab)" Rift and drift stage "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" Fayston Formation Carbonaceous albite schist member Metasedimentary Lower Cambrian and Neoproterozoic CZfco CZfco 30 0 0 0 134 bedrock conglomerate dolostone Lower part (not shown on map) largely cream- to beige-weathering massive dolostone and boulder and cobble dolostone conglomerate Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Forestdale Formation Dolostone member Metasedimentary Lower Cambrian and Neoproterozoic CZfd CZfd 30 0 0 0 133 bedrock dolostone metasandstone Upper part consists of orangey-tan- to brown-weathering quartz-pebble dolostone and dolomitic crossbedded feldspathic metasandstone Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Forestdale Formation Dolostone member Metasedimentary Lower Cambrian and Neoproterozoic CZfp CZfp 10 15 37 0 166 bedrock phyllite "Light-gray to light-green, quartz-sericite-chlorite (+/-magnetite+/-biotite) phyllite" "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" Fairfield Pond Formation Metasedimentary Cambrian and Neoproterozoic CZfq CZfq 27 29 55 0 135 bedrock quartzite Grayish-tan to light-gray vitreous quartzite and white feldspathic gritty quartzite Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Forestdale Formation Quartzite member Metasedimentary Lower Cambrian and Neoproterozoic CZfqz CZfqz 27 29 55 0 181 bedrock quartzite "White quartzite and tan to light-gray, medium-grained muscovite quartzite locally rich in magnetite. Resembles quartzite of the Tyson Formation (CZtq)" Rift and drift stage "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" Fayston Formation Quartzite member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZfs CZfs 34 33 73 0 182 bedrock schist "Silvery-green to rusty-tan, fine-grained chlorite-quartz-sericite (+/-garnet+/-chloritoid+/-allanite) phyllite. Resembles green phyllites of the Pinney Hollow Formation (CZph), Mount Abraham Formation (CZa), and Tyson Formation (CZtg)" Rift and drift stage "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" Fayston Formation Schist member Metasedimentary Lower Cambrian and Neoproterozoic CZfw CZfw 18 35 55 0 178 bedrock metawacke gneiss "Salt-and-pepper-colored, medium- to coarse-grained quartz-albite-biotite gneiss" Rift and drift stage "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" Fayston Formation Foliated metawacke member Metasedimentary Lower Cambrian and Neoproterozoic CZh CZh 29 33 41 0 195.5 bedrock schist quartzite "Heterogeneous unit consisting mainly of dark-gray to medium-light-gray-weathering, white-plagioclase-studded schist, gray slabby quartz-rich muscovite (+/-garnet) schist and layers of dark-gray biotitic quartzite and metawacke" Rift and drift stage Eastern flank of the Green Mountain massif and eastern domes Hoosac Formation Unvidided Metasedimentary Lower Cambrian and Neoproterozoic CZhab CZhab 24 20 31 0 205 bedrock granofels schist "Light-gray- to whitish-gray-weathering, massive to thickly bedded medium-grained biotite-white albite-quartz granofels, locally is a medium-gray, finer grained, more biotite-rich albitic quartz schist of gneissic aspect" Rift and drift stage Eastern flank of the Green Mountain massif and eastern domes Hoosac Formation Albite-quartz granofels member Metasedimentary Lower Cambrian and Neoproterozoic CZhabc CZhabc 53 52 63 0 206 bedrock granofels conglomerate "Light-gray, massive, coarse-grained biotite-white albite-quartz granofels like CZhab but containing boulders of pegmatite and of granitic gneiss, and disarticulated beds of albitic granofels as pseudoconglomerate" Rift and drift stage Eastern flank of the Green Mountain massif and eastern domes Hoosac Formation Albite granofels and gneiss-boulder conglomerate member Metasedimentary Lower Cambrian and Neoproterozoic CZhbs CZhbs 29 22 53 0 197 bedrock schist phyllite "Coal-black, lustrous, rusty- to non-rustyweathering, biotite-muscovite-plagioclase-quartz schist and phyllite, containing lenses of white laminated quartzite as beds and discoidal boudins" Rift and drift stage Eastern flank of the Green Mountain massif and eastern domes Hoosac Formation Biotite phyllite member Metasedimentary Lower Cambrian and Neoproterozoic CZhc CZhc 61 100 0 0 207 bedrock conglomerate quartzite "Light-grayish-tan-weathering, biotite-muscovite-quartz conglomerate and pebbly muscovite quartzite, and dark-medium-gray blue-quartz biotite quartzite and schist" Rift and drift stage Eastern flank of the Green Mountain massif and eastern domes Hoosac Formation Conglomerate and quartzite member Metasedimentary Lower Cambrian and Neoproterozoic CZhcgt CZhcgt 29 50 62 0 196 bedrock schist "Lustrous, green, ilmenite-chlorite-chloritoid-garnet-muscovite-quartz (+/-paragonite) schist resembles, Pinney Hollow Formation but lacks amphibolite. Aluminous schists at Devils Den and aluminous rocks of the Cavendish Formation may be correlative" Rift and drift stage Eastern flank of the Green Mountain massif and eastern domes Hoosac Formation Garnet schist member Metasedimentary Lower Cambrian and Neoproterozoic CZhd CZhd 45 14 14 0 199 bedrock marble quartzite "Light-gray-, cream- or pinkish-gray-weathering, medium- to fine-grained phlogopite-quartz-dolomite marble. Occurs as thin beds in gray albitic granofels member (CZhab), locally contains beds of vitreous to bluish-gray laminated quartzite" Rift and drift stage Eastern flank of the Green Mountain massif and eastern domes Hoosac Formation Dolomite marble member Metasedimentary Lower Cambrian and Neoproterozoic CZhgab CZhgab 34 25 56 0 204 bedrock granofels schist "Pale-green to light-greenish-gray, chlorite-magnetite-white-albite-spotted-quartz granofels and schist" Rift and drift stage Eastern flank of the Green Mountain massif and eastern domes Hoosac Formation Chlorite albite schist and granofels member Metasedimentary Lower Cambrian and Neoproterozoic CZhgt CZhgt 29 27 36 0 203 bedrock schist "Medium-dark-gray to lustrous silvery-gray garnet-biotite-muscovite-plagioclase-quartz schist and feldspathic garnet schist, associated with CZhs member which it laterally replaces" Rift and drift stage Eastern flank of the Green Mountain massif and eastern domes Hoosac Formation Garnet biotite schist member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZhn CZhn 14 13 25 0 173 bedrock schist quartzite "Dark-rusty-brown graphitic biotite-muscovite-chlorite-quartz (+/-garnet) schist and gneiss, dark-albite porphyroblasts, large euhedral pyrite, and beds of dark-gray quartzite are common" Rift and drift stage "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" Hazens Notch Formation Undivided Metasedimentary Cambrian and Neoproterozoic simplified description CZhng CZhng 70 13 50 0 174 bedrock greenstone amphibolite "Dark green, pitted-weathering, mafic schist to massive greenstone with chlorite, albite, carbonate, epidote, amphibole and sphene, and amphibolite with hornblende, actinolite, albite, chlorite, epidote, biotite, magnetite and sphene" Rift and drift stage "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" Hazens Notch Formation Greenstone and amphibolite member Metavolcanic Cambrian and Neoproterozoic simplified description CZhnn CZhnn 44 35 69 0 175 bedrock schist "Rusty-weathering, non-graphitic, sulfidic chlorite-muscovite-quartz schist" Rift and drift stage "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" Hazens Notch Formation Schist member Metasedimentary Cambrian and Neoproterozoic CZhq CZhq 14 63 63 0 201 bedrock quartzite "Light-gray-, yellowish-gray- to dark-dull-gray-weathering, biotite or muscovite quartzite, feldspathic quartzite, and pebbly muscovitic quartzite, commonly occuring as basal member or as layers in schist member (CZhs)" Rift and drift stage Eastern flank of the Green Mountain massif and eastern domes Hoosac Formation Quartzite member Metasedimentary Lower Cambrian and Neoproterozoic CZhrab CZhrab 19 18 34 0 200 bedrock schist granofels "Rusty-weathering, medium- to dark-gray, black albite-biotite-quartz schist and granofels, marked by large spangles of muscovite and weathered-out pits of dolomite or ankerite" Rift and drift stage Eastern flank of the Green Mountain massif and eastern domes Hoosac Formation Albite schist and granofels member Metasedimentary Lower Cambrian and Neoproterozoic CZhs CZhs 11 16 27 0 202 bedrock schist quartzite "Lustrous, dark-gray to silvery-gray tourmaline-muscovitebiotite-quartz schist and steel-gray muscovitic quartzite" Rift and drift stage Eastern flank of the Green Mountain massif and eastern domes Hoosac Formation Schist member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZhtm CZhtm 60 60 0 0 198 bedrock amphibolite greenstone "Dark green to black hornblende-plagioclase (+/-garnet+/-epidote) amphibolite and grayish-green epidote-plagioclase ankeritic greenstone, grades into epidote-quartz-plagioclase volcaniclastic wacke. Occurs as lenses at multiple stratigraphic levels" Rift and drift stage Eastern flank of the Green Mountain massif and eastern domes Hoosac Formation Turkey Mountain Metabasalt Member Metavolcanic Lower Cambrian and Neoproterozoic CZj CZj 25 41 59 0 298 bedrock phyllite quartzite "Light-grayish-green, fine-grained, chlorite-muscovite-quartz phyllite or schist and quartzite, white quartzofeldspathic layers alternate with green chloritic phyllitic layers, locally albitic" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Jay Peak Formation Schist member Metasedimentary Cambrian and Neoproterozoic CZjg CZjg 100 19 69 0 299 bedrock greenstone "Green, carbonate-albite-epidote-chlorite greenstone" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Jay Peak Formation Greenstone member Metavolcanic Cambrian and Neoproterozoic CZmf CZmf 0 40 100 0 129 bedrock granofels quartzite "Gray to dark-gray, biotite-albite-quartz granofels and flaser-bedded tan to gray feldspathic quartzite, latter resembles similar rock of the Dalton Formation (CZdfq), whereas the former resembles albitic rocks of the Hoosac Formation (CZhab)" Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Moosalamoo Formation Feldspathic quartzite and granofels member Metasedimentary Lower Cambrian and Neoproterozoic CZmmt CZmmt 38 47 62 0 132 bedrock metasiltstone conglomerate "Grayish-brown- to pale-green-weathering, well-laminated, magnetite-studded chloritic metasiltstone, near base contains magnetite-cemented quartz-pebble conglomerate and bedded magnetite quartzite" Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Moosalamoo Formation Magnetite metasiltstone member Metasedimentary Lower Cambrian and Neoproterozoic CZmp CZmp 27 29 55 0 131 bedrock phyllite metawacke "Dark-gray, sooty-weathering, splintery sulfidic to non-sulfidic quartz phyllite and pebbly and gritty biotite metawacke" Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Moosalamoo Formation Gray phyllite and metawacke member Metasedimentary Lower Cambrian and Neoproterozoic CZmpq CZmpq 27 29 55 0 339 bedrock quartzite "Buff- to gray-weathering vitreous quartzite as much as 6 m thick, containing deeply weathered ovoidal areas of carbonate-cemented quartzite" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Bull Formation Mud Pond Quartzite Member Metasedimentary Lower Cambrian CZmq CZmq 50 50 70 0 130 bedrock quartzite conglomerate "Light-tan to gray, vitreous and non-vitreous quartzite and feldspathic quartzite and quartz conglomerate" Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Moosalamoo Formation Quartzite member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZmt CZmt 34 43 52 0 183 bedrock schist metawacke "Gray- to rusty-brown garnet-biotite-muscovite-quartz schist, gray albitic biotite-quartz granofels, light-gray to steel-gray biotite, minor epidote-magnetite-actinolite-chlorite feldspathic wacke, and chlorite-muscovite-albite granofels and phyllite" Rift and drift stage Eastern flank of the Green Mountain massif and eastern domes Monastery Formation Heterogeneous schist quartzite and granofels Metasedimentary Cambrian and Neoproterozoic simplified description CZmtg CZmtg 45 55 100 0 184 bedrock quartzite Beds of gritty feldspathic quartzite in CZtm Rift and drift stage Eastern flank of the Green Mountain massif and eastern domes Monastery Formation Quartztite Metasedimentary Cambrian and Neoproterozoic simplified description CZn CZn 16 12 40 0 350 bedrock phyllite metasiltstone Predominantly light- to medium-gray and grayish-green phyllite and metasiltstone The Taconic Allochthon Rocks of the Dorset Mountain Slice Netop Formation phyllite and metasiltstone Metasedimentary Cambrian and Neoproterozoic simplified description CZnab CZnab 44 34 73 0 353 bedrock metasiltstone Greenish-gray laminated albite-metasiltstone The Taconic Allochthon Rocks of the Dorset Mountain Slice Netop Formation albite-metasiltstone Metasedimentary Cambrian and Neoproterozoic simplified description CZnb CZnb 27 27 37 0 341 bedrock wacke siltstone "Pale-reddish-brown to light-gray-weathering, medium- and fine-grained, massive to thickly bedded, olive-green to gray, micaceous quartz-feldspar greywacke and siltstone, with coarse detrital muscovite, biotite and autoclastic slate chips" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Bull Formation and Nassau Formation Bomoseen Member of the Nassau Formation Metasedimentary Neoproterozoic simplified description CZngq CZngq 31 23 71 0 355 bedrock conglomerate wacke "Beds of grayish-green vitreous quartzite and quartz-pebble conglomerate, and thin beds of chloritic wacke" The Taconic Allochthon Rocks of the Dorset Mountain Slice Netop Formation Chlorite phyllite member Metasedimentary Cambrian and Neoproterozoic simplified description CZngs CZngs 12 10 29 0 354 bedrock phyllite metasiltstone "Light-green to gray, lustrous, chlorite+/-chloritoid-muscovite-quartz phyllite and greenish-gray metasiltstone" The Taconic Allochthon Rocks of the Dorset Mountain Slice Netop Formation Chlorite phyllite member Metasedimentary Cambrian and Neoproterozoic simplified description CZnm CZnm 11 8 36 0 343 bedrock phyllite limestone "Greenish-gray to pale-lustrous-green chlorite-muscovite-quartz phyllite, and green and purple, bedded and mottled phyllite. Locally contains boudins and thin beds of limestone and pods of pinkish-gray to cream-white dolostone, and minor quartzite" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Bull Formation and Nassau Formation Mettawee Member of the Nassau Formation Metasedimentary Neoproterozoic simplified description CZnq CZnq 29 39 61 0 351 bedrock dolostone quartzite Dark-gray phyllite containing bluish-gray dolostone and tan-weathering to locally mappable gray-weathering dolomitic quartzite The Taconic Allochthon Rocks of the Dorset Mountain Slice Netop Formation dolostone and dolomitic quartzite Metasedimentary Cambrian and Neoproterozoic CZnr CZnr 35 24 41 0 347 bedrock wacke Graywacke The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Nassua Formation Rensselaer Graywacke Member Metasedimentary Lower Cambrian and Neoproterozoic CZnw CZnw 19 25 55 0 356 bedrock wacke "Bluish-gray, fine-grained metawacke and metasiltstone, perhaps equivalent to the Bomoseen Graywacke Member of the Bull Formation" The Taconic Allochthon Rocks of the Dorset Mountain Slice Netop Formation Wacke member Metasedimentary Cambrian and Neoproterozoic CZpc CZpc 28 37 79 0 138 bedrock metawacke phyllite "Feldspathic biotite phyllitic metawacke interlayered with lenses of quartz, feldspar, and gneiss-pebble to -cobble conglomerate" Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Pinnacle Formation Light-gray phyllitic conglomerate member Metasedimentary Cambrian and Neoproterozoic CZpcg CZpcg 35 47 100 0 143 bedrock conglomerate schist "Poorly sorted, matrix-supported quartz- and gneiss-cobble to boulder conglomerate, locally containing quartzite boulders as large as 3 m, in a matrix of gray-weathering magnetite-calcite-chlorite-muscovite-biotite-feldspar schist" Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Pinnacle Formation Cobble and and boulder conglomerate member Metasedimentary Cambrian and Neoproterozoic simplified description CZph CZph 31 21 61 0 182.2 bedrock phyllite schist "Light-greenish-gray to lustrous pale-green, chlorite-muscovite-quartz (+/-chloritoid+/-garnet+/-magnetite) phyllite. Chloritoid-rich rocks (CZphc) appear gritty owing to distributed porphyroblasts of chloritoid, locally albitic, contains minor beds of quartzite" Rift and drift stage Cover rocks of Green Mountain anticlinorium Pinney Hollow Formation Phyllite member Metasedimentary Cambrian and Neoproterozoic simplified description CZpha CZpha 73 13 73 0 182.8 bedrock amphibolite greenstone "Dark-green to black plagioclase-biotite-hornblende (+/-quartz) amphibolite, epidote amphibolite, and ankeritic chlorite-magnetite-plagioclase (albite) greenstone" Rift and drift stage Cover rocks of Green Mountain anticlinorium Pinney Hollow Formation Amphibolite and greenstone member Metavolcanic Cambrian and Neoproterozoic CZphb CZphb 48 37 47 0 182.7 bedrock schist phyllite "Dark-gray to black, sulfidic biotite-plagioclase-quartz schist, commonly interbedded with or adjacent to amphibolite and greenstone member (CZpha), locally is a silvery-gray sulfidic biotite phyllite" Rift and drift stage Cover rocks of Green Mountain anticlinorium Pinney Hollow Formation Black phyllite member Metasedimentary Cambrian and Neoproterozoic simplified description CZphc CZphc 31 21 61 0 182.4 bedrock phyllite schist Chloritoid-rich chlorite-muscovite-quartz phyllite schist or phyllite that appears gritty owing to distributed porphyroblasts of chloritoid Rift and drift stage Cover rocks of Green Mountain anticlinorium Pinney Hollow Formation Chloritoid-rich schist member Metasedimentary Cambrian and Neoproterozoic CZphf CZphf 41 47 47 0 182.9 bedrock metafelsite feldspathic quartzite "White to pale-green, laminated to massive, epidote-calcite-muscovite-quartz-albite metarhyolitic gneiss or schist, a volcanic or volcaniclastic rock. Contains purplish gray feldspathic quartzite" Rift and drift stage Cover rocks of Green Mountain anticlinorium Pinney Hollow Formation Metafelsite member Metavolcanic Cambrian and Neoproterozoic CZphq CZphq 13 20 70 0 182.5 bedrock schist "Light-gray to gray-green, laminated, gritty feldspathic chlorite-muscovite-plagioclase-quartz schist" Rift and drift stage Cover rocks of Green Mountain anticlinorium Pinney Hollow Formation Feldspathic quartz schist member Metasedimentary Cambrian and Neoproterozoic CZphw CZphw 50 60 70 0 182.6 bedrock metawacke "Silvery-gray, pinstriped, coarse- to medium-grained, blue-quartz-pebble chlorite-biotite-plagioclase-quartz metawacke, locally conglomeratic and rich in epidote" Rift and drift stage Cover rocks of Green Mountain anticlinorium Pinney Hollow Formation Metawacke member Metasedimentary Cambrian and Neoproterozoic CZpq CZpq 43 33 37 0 142 bedrock conglomerate quartzite Light gray quartz-feldspar conglomerate and quartzite Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Pinnacle Formation Quartzite and quartz-pebble conglomerate member Metasedimentary Cambrian and Neoproterozoic simplified description CZps CZps 24 24 39 0 141 bedrock metawacke phyllite "Light gray, medium-grained, massive quartz-sericite-chlorite-albite metawacke, and gray to grayish-green magnetite-chlorite-muscovite-quartz schist, and phyllite or pebbly phyllite, locally rich in magnetite" Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Pinnacle Formation Metawacke and phyllite member Metasedimentary Cambrian and Neoproterozoic simplified description CZpu CZpu 30 30 40 0 137 bedrock schist metawacke "Gray, foliated muscovite-chlorite-biotite-feldspar-quartz schist, phyllite and metagraywacke. Blue quartz, conglomeratic horizons, feldspathic biotite phyllitic metawacke with lenses of quartz, feldspar and gneiss pebble- to cobble-conglomerate (CZpc)" Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Pinnacle Formation Pinnacle Formation undivided Metasedimentary Cambrian and Neoproterozoic CZpv CZpv 70 9 70 0 144 bedrock greenstone Largely carbonate-epidote-albite-chlorite+/-actinolite greenstones Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Pinnacle Formation "Metabasalt and volcaniclastic rocks, undifferentiated" Metavolcanic Cambrian and Neoproterozoic CZpva CZpva 70 9 70 0 145 bedrock greenstone Calcite-biotite-sphene-albite-actinolite-epidote-chlorite greenstone with dark green porphyroblasts of actinolitic hornblende Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Pinnacle Formation Amphibolitic greenstone member Metavolcanic Cambrian and Neoproterozoic CZpvc CZpvc 70 9 70 0 146 bedrock greenstone metawacke "Rusty-weathering and pitted, dark-green greenstone with laminae and splotches of calcareous material, locally interbedded with calcareous metagraywacke" Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Pinnacle Formation Calcareous greenstone member Metavolcanic Cambrian and Neoproterozoic CZpvf CZpvf 70 9 70 0 147 bedrock greenstone "Olive-drab-weathering, dark-green, fine-grained greenstone with remnant plagioclase feldspar phenocrysts up to 1.5 cm in diameter" Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Pinnacle Formation Feldspathic greenstone member Metavolcanic Cambrian and Neoproterozoic simplified description CZpw CZpw 18 35 55 0 139 bedrock metawacke conglomerate "Gray- to light-brownish-gray-weathering, massive to bedded muscovite-biotite-chlorite metawacke, conglomerate, and blue-quartz pebbly phyllite, wacke and feldspathic quartzite" Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Pinnacle Formation Metawacke member Metasedimentary Cambrian and Neoproterozoic simplified description CZpwd CZpwd 59 57 39 0 140 bedrock metawacke dolostone "Heterogeneous unit consists of coarse- to medium-grained clastic wacke, beige-weathering dolostone, and quartz-rich dolostone" Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Pinnacle Formation Metawacke member Metasedimentary Cambrian and Neoproterozoic simplified description CZra CZra 75 17 100 0 309 bedrock amphibolite "Very dark green to black, finely foliated biotite-plagioclase amphibolite to dark-green to light-greenish-gray, chlorite-plagioclase-ankerite greenstone and interlayered gray biotitic feldspathic volcaniclastic rock and feldspathic quartzite" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Rowe Schist Amphibolite member Metavolcanic Cambrian and Neoproterozoic? simplified description CZrc CZrc 41 47 47 0 315 bedrock schist quartzite "Dark-gray- to sooty-gray-weathering, sulfidic, graphitic biotite-muscovite-plagioclase-quartz schist, containing thin beds of dark-bluish-gray vitreous quartzite" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Rowe Schist Graphitic schist and quartzite member Metasedimentary Cambrian and Neoproterozoic? simplified description CZrch CZrch 24 45 55 0 314 bedrock schist gneiss "Dark-gray or green, dull-gray- and rusty-weathering, slabby, well-foliated, quartz-rich muscovite-biotite-plagioclase-quartz schist, garnet schist, and splintery chlorite-chloritoid-muscovite-plagioclase (+/-garnet)-quartz schist, with minor feldspathic biotite gneiss" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Rowe Schist Cooper Hill Member Metasedimentary Cambrian and Neoproterozoic? CZrfb CZrfb 47 41 71 0 313 bedrock schist gneiss "Gray and light-gray-weathering, medium- to coarse-grained biotite-plagioclase-sericite-quartz schist and gneiss, commonly flecked with large cross-biotite. Locally contains coarse garnet" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Rowe Schist Biotite-plagioclase schist and gneiss member Metasedimentary Cambrian and Neoproterozoic? CZrgs CZrgs 25 19 29 0 312 bedrock schist "Mainly yellowish-green, lustrous, biotite-chlorite-muscovite-plagioclase-quartz-garnet schist, distinguished by large garnets and coarse cross-biotite. Typical of rocks within the Stowe Formation elsewhere" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Rowe Schist Garnet schist member Metasedimentary Cambrian and Neoproterozoic? CZrr CZrr 23 31 69 0 316 bedrock schist "Rusty-gray- to yellowish-brown-weathering, lustrous, non-carbonaceous, well-foliated chlorite-quartz-muscovite (+/-plagioclase) schist" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Rowe Schist Chlorite schist member Metasedimentary Cambrian and Neoproterozoic? CZrrgt CZrrgt 23 31 69 0 317 bedrock schist "Dark-grayish-brown-weathering, coarse-grained garnet-biotite-plagioclase-quartz schist" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Rowe Schist Garnet-biotite feldspathic schist member Metasedimentary Cambrian and Neoproterozoic? CZrs CZrs 25 19 29 0 311 bedrock phyllite schist "Pale-green to dark-green, lustrous, magnetite-chlorite-muscovite-quartz phyllite and schist, highly tectonically laminated near larger ultramafic bodies (CZu). Unit typical of lustrous chloritic schists of the Stowe Formation, farther north" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Rowe Schist Chlorite phyllite member Metasedimentary Cambrian and Neoproterozoic? simplified description CZs CZs 19 21 39 0 289 bedrock phyllite schist "Fine-grained, lustrous, well-foliated, silvery green, grayish-green, and bright-green, quartz-ribbed and -knotted, magnetite-chlorite (biotite)-albite (plagioclase)-sericite (muscovite) quartz phyllite and schist" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Stowe Formation Schist and phyllite member Metasedimentary Cambrian and Neoproterozoic? simplified description CZsa CZsa 100 19 69 0 294 bedrock amphibolite "Dark-green hornblende-rich-biotite plagioclase (+/-garnet) amphibolite, epidote-hornblende-plagioclase-quartz amphibolite" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Stowe Formation Amphibolite and greenstone member Metavolcanic Cambrian and Neoproterozoic? CZsbg CZsbg 25 29 67 0 292 bedrock phyllite "Interlayered grayish-green and rusty-weathering black quartzose phyllite, similar to dark carbonaceous phyllites of the Ottauquechee Formation (Co)" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Stowe Formation Carbonaceous phyllite member Metasedimentary Cambrian and Neoproterozoic? simplified description CZsd CZsd 19 21 39 0 290 bedrock phyllite metadiabase Same as CZs but with abundant dikes of metadiabase Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Stowe Formation Schist and phyllite member Metasedimentary Cambrian and Neoproterozoic? simplified description CZsg CZsg 100 19 69 0 295 bedrock greenstone "Light-grayish-green, rusty weathering, carbonate-pitted, ankerite-magnetite-albite-epidote (plagioclase) feldspathic greenstone and interbedded feldspathic quartzite" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Stowe Formation Amphibolite and greenstone member Metavolcanic Cambrian and Neoproterozoic? CZsgp CZsgp 38 37 81 0 291 bedrock phyllite schist Quartz-sericite phyllite and schist Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Stowe Formation Sericite schist member with metadiabase dikes Metasedimentary Cambrian and Neoproterozoic? simplified description CZsgt CZsgt 19 21 39 0 293 bedrock schist Silvery-green to grayish-green garnet (large)-plagioclase-biotite (chlorite) quartz-muscovite schist. Comparable to CZrgs in Rowe Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Stowe Formation Large-garnet schist member Metasedimentary Cambrian and Neoproterozoic? CZsp CZsp 13 80 30 0 369 bedrock serpentinite "Brown-weathering, dark-green serpentinite" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Ultramafic rocks Serpentinite Metavolcanic / Metaplutonic Cambrian and Neoproterozoic CZswa CZswa 77 21 65 0 297 bedrock amphibolite "Dark-green to black, massive, medium- to coarse-grained, layered albite-epidote-hornblende amphibolite, possibly is a meta-intrusive. Exposed in the Worcester Mountains" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Stowe Formation Amphibolite member Metavolcanic Cambrian and Neoproterozoic? CZsws CZsws 13 50 60 0 296 bedrock schist "Silvery-blue, medium- to coarse-grained chlorite-muscovite-quartz schist (+/-garnet+/-kyanite+/-chloritoid); contains characteristic spangly muscovite and elongated knots of quartz and layers of pinkish coticule" Rift and drift stage Allochthonous cover sequence east of the Green Mountains Rowe Hawley Zone Stowe Formation Kyanite schist member Metasedimentary Cambrian and Neoproterozoic? CZt CZt 33 36 47 0 187 bedrock phyllite metawacke Phyllite and metawacke. Shown east of Rutland Rift and drift stage Eastern and western flank of the Green Mountain massif Tyson Formation Unvidided Metasedimentary Lower Cambrian and Neoproterozoic CZtab CZtab 34 25 56 0 188 bedrock granofels schist "Gray and greenish-gray, magnetite-chlorite-(biotite)-muscovite-albite-quartz granofels and schist. Similar to gray or green albitic granofels of the Hoosac Formation (CZhab and CZhgab)" Rift and drift stage Eastern and western flank of the Green Mountain massif Tyson Formation Albitic magnetite granofels member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZtagn CZtagn 47 44 38 0 359 bedrock gneiss "White, light-gray- and green-banded, epidote-white mica-quartz-albite (+/-garnet+/-magnetite) gneiss with plagioclase and polycrystalline quartz porphyroblasts. Green, chloritic layers 2 to 10 cm thick also contain chlorite pseudomorphs after garnet" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Tillotson Peak Structural Complex Albite gneiss Metasedimentary Cambrian CZtbs CZtbs 36 53 74 0 194 bedrock phyllite schist "Dark-gray to black, locally carbonaceous, rusty-brown-weathering biotite-rich quartz schist and dark biotite-albite schist" Rift and drift stage Eastern and western flank of the Green Mountain massif Tyson Formation Albite schist member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZtc CZtc 61 100 0 0 195 bedrock conglomerate metawacke "Massive to well-bedded chlorite-biotite(+/-albite)-quartz-pebble, -cobble, and -boulder conglomerate, feldspathic conglomeratic metawacke, and locally a dolomite-cemented feldspathic quartz-pebble conglomerate" Rift and drift stage Eastern and western flank of the Green Mountain massif Tyson Formation Conglomerate member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZtd CZtd 30 0 0 0 193 bedrock dolostone phyllite "Largely massive, gray-, beige-, and pinkish-gray-weathering dolostone, beds of pebbly quartz dolostone, and pink- to orange-tan-weathering dolostone as lenses in phyllite. Contains beds of bluish-gray and whitish-gray vitreous quartzite. Similar to CZfd" Rift and drift stage Eastern and western flank of the Green Mountain massif Tyson Formation Dolostone member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZtg CZtg 26 45 63 0 189 bedrock phyllite schist "Pale-greenish-gray to yellowish- greenish-gray, chlorite-muscovite-quartz phyllite and schist, locally contains beds of pebbly metawacke and magnetite phyllite" Rift and drift stage Eastern and western flank of the Green Mountain massif Tyson Formation Chlorite muscovite phyllite and schist member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZtgr CZtgr 26 26 71 0 191 bedrock metawacke phyllite "Gray to grayish-green, biotite-chlorite-quartz-pebble phyllite. Albitic biotite-(chlorite)-quartz granofels and wacke locally present" Rift and drift stage Eastern and western flank of the Green Mountain massif Tyson Formation Quartz-pebble phyllite and wacke member Metasedimentary Lower Cambrian and Neoproterozoic simplified description CZth CZth 70 13 70 0 148 bedrock greenstone metabasalt "Metabasalt and minor metasedimentary rocks, massive fine-grained, dark-green metabasalt flows, pillow basalt, vesicular basalt, interbedded phyllitic grits, feldspathic quartzite, chloritic metawacke and basaltic tuffaceous metasedimentary rock" Cover rocks of the Lincoln Mountain massif and northwestern flank of the Green Mountain massif Tibbit Hill Formation Metavolcanic Cambrian and Neoproterozoic simplified description CZtm CZtm 69 23 41 0 357 bedrock blueschist ecolgite "Blueschist of amphibole (glaucophane, barroisite, actinolite), epidote, garnet, chlorite, magnetite, pyrite, apatite with quartz and garnet coticule. Green eclogite of garnet, omphacite, glaucophane, epidote, quartz, albite and white mica" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Tillotson Peak Structural Complex Mafic schist and amphibolite Metavolcanic / Metaplutonic Cambrian CZtp CZtp 20 20 50 0 358 bedrock schist "Silvery-gray medium-grained schist composed of white mica, quartz, chlorite (+/-garnet+/-albite+/-glaucophane+/-chloritoid) local cm-thick lenses of coticule" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Tillotson Peak Structural Complex Pelitic schist Metasedimentary Cambrian CZtq CZtq 39 36 31 0 192 bedrock quartzite dolostone "Gray to very light-gray, vitreous and nonvitreous, massive to thin-bedded quartzite, magnetite and biotite quartzite, and feldspathic quartzite, locally interbedded with dolostone. Similar to quartzites in the Forestdale Formation (CZfq)" Rift and drift stage Eastern and western flank of the Green Mountain massif Tyson Formation Quartzite member Metasedimentary Lower Cambrian and Neoproterozoic CZtrg CZtrg 31 29 59 0 190 bedrock phyllite metawacke "Rusty-weathering, gray to grayish-green, chlorite-muscovite-quartz phyllite and minor beds of pebbly-quartz metawacke" Rift and drift stage Eastern and western flank of the Green Mountain massif Tyson Formation Quartz phyllite member Metasedimentary Lower Cambrian and Neoproterozoic CZu CZu 33 100 40 0 366 bedrock serpentinite dunite "Brown- to white-weathering, green, massive, moderately to fully serpentinized dunite and peridotite and schistose serpentinite, rusty-weathering medium-grained talc-carbonate rock and quartz-carbonate (magnesite) rock" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Ultramafic rocks "Meta-ultramafic rocks, undifferentiated" Metavolcanic / Metaplutonic Cambrian and Neoproterozoic simplified description CZun CZun 13 20 50 0 168 bedrock schist phyllite "Silvery-green quartz-muscovite-chlorite schist and phyllite, commonly with albite and magnetite, locally contains dolomite" Rift and drift stage "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" Underhill Formation Schist and phyllite member Metasedimentary Cambrian and Neoproterozoic simplified description CZung CZung 70 13 50 0 171 bedrock greenstone amphibolite "Carbonate-albite- epidote greenstone and massive magnetite-albite-amphibole-biotite-epidote amphibolite, light to dark green, epidote-chlorite-albite-amphibole schist; dark green, weakly foliated epidote-biotite-albite-amphibole amphibolite" Rift and drift stage "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" Underhill Formation Greenstone and amphibolite member Metavolcanic Cambrian and Neoproterozoic simplified description CZungs CZungs 16 13 30 0 169 bedrock schist Quartz-muscovite-chlorite schist and phyllite +/-biotite with garnet porphyoblasts Rift and drift stage "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" Underhill Formation Garnet schist member Metasedimentary Cambrian and Neoproterozoic simplified description CZunql CZunql 36 43 72 0 172 bedrock schist mylonite "Light-gray to tan and rusty-weathering, fine-grained, well-foliated mylonitic albite-chlorite-muscovite-quartz (+/-dolomite) laminated schist" Rift and drift stage "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" Underhill Formation Quartz laminated schist member Metasedimentary Cambrian and Neoproterozoic simplified description CZunw CZunw 43 42 50 0 170 bedrock metawacke granofels "Local lenses of white to pale-gray quartzite, quartz-albite granofels, and quartz-granule chlorite (+/-biotite) metawacke" Rift and drift stage "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" Underhill Formation Metawacke member Metasedimentary Cambrian and Neoproterozoic CZutc CZutc 13 80 30 0 368 bedrock schist "Cream-colored to light-bluish-gray, brown-weathering, talc-carbonate schist and talc-carbonate-rich rocks" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Ultramafic rocks Talc-carbonate schist Metavolcanic / Metaplutonic Cambrian and Neoproterozoic CZwb CZwb 30 0 0 0 167 bedrock dolostone sandstone "Buff to cream-colored massive dolomite and dolomitic sandstone, containing prominent zone of massive and specular hematite near top at Sheldon" "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" White Brook Formation Metasedimentary Cambrian and Neoproterozoic simplified description CZzh CZzh 47 29 43 0 344 bedrock quartzite conglomerate "Light-greenish-gray to whitish-gray-weathering, massive vitreous quartzite, locally quartz-pebble conglomerate and wacke near the base" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Bull Formation Zion Hill Quartzite Member Metasedimentary Lower Cambrian and Neoproterozoic simplified description d d 85 29 19 0 333 bedrock dolostone "Pods, lenses or zones of thinly bedded dolostone" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Bull West Castleton and Hatch Hill Formations dolostone member Metasedimentary Cambrian and Neoproterozoic? Dabg Dabg 0 36 30 0 36 bedrock granite pegmatite "Gray to pink, medium- to coarse-grained garnet-muscovite-biotite granite and pegmatite, undifferentiated" New Hampshire Plutonic Suite Northeast Kingdom batholith Averill pluton granite and pegmatite Plutonic Devonian simplified description Dbbg Dbbg 0 55 45 0 42 bedrock granite "Gray, homogeneous, fine- to medium-grained muscovite-biotite granodiorite" New Hampshire Plutonic Suite Other plutons of the New Hampshire Plutonic Suite East Barre plutons muscovite-biotite granite Plutonic Devonian Dbg Dbg 0 45 38 0 21 bedrock granite granodiorite "Binary and biotite granite and granodiorite, undifferentiated" New Hampshire Plutonic Suite Devonian intrusive rocks binary and biotite granite and granodiorite Plutonic Devonian simplified description Dbgn Dbgn 30 20 13 0 463 bedrock quartz monzonite "Medium- to coarse-grained, equigranular to porphyritic, muscovite-biotite-microcline-plagioclase metaquartz monzonite, contains garnet, sillimanite-andalusite and cordierite" Bronson Hill anticlinorium or arch Bronson Hill arch intrusive rocks Bethlehem Gneiss Metaplutonic Early Devonian simplified description Dbmg Dbmg 0 55 45 0 47 bedrock granite pegmatite "Weakly foliated, light-gray to whitish gray, garnet-biotite-muscovite granite, minor pegmatite and aplite dikes (Dg)" New Hampshire Plutonic Suite Devonian granitic rocks of southern Vermont Black Mountain pluton of the Guilford dome granite Plutonic Devonian Dbqm Dbqm 0 64 53 0 43 bedrock monzonite "Very light-bluish gray to white, medium-grained, muscovite-biotite quartz monzonite, locally orbicular, commercially known as Bethel white and similar to the predominantly lighter-colored granitic rocks of southern Vermont" New Hampshire Plutonic Suite Other plutons of the New Hampshire Plutonic Suite East Bethel plutons quartz monzonite Plutonic Devonian Dco Dco 30 30 13 0 425 bedrock metasandstone slate "Light-gray to tan, micaceous, locally calcareous metasandstone and slate or metamudstone in beds a few cm to tens of cm thick. Graded bedding common. Interpreted to be correlative with the Gile Mountain Formation" Connecticut Valley Trough Connecticut Valley Trough Compton Formation Metasandstone member Metasedimentary Lower Devonian Dcoa Dcoa 70 8 70 0 426 bedrock amphibolite Garnetiferous hornblende schist and minor hornblende amphibolite Connecticut Valley Trough Connecticut Valley Trough Compton Formation Amphibolite member Metavolcanic Lower Devonian Dd Dd 100 40 0 0 46 bedrock metadiorite diorite "Biotite metadiorite in unit Dgq northeast of St. Johnsbury - Medium-light-bluish-gray, fine-grained, foliated and lineated" New Hampshire Plutonic Suite Other plutons of the New Hampshire Plutonic Suite Biotite metadiorite in unit Dgq northeast of St. Johnsbury metadiorite Plutonic Devonian Ddbg Ddbg 0 64 53 0 24 bedrock granodiorite tonalite "Light-gray, medium- to coarse-grained, massive, epidote-biotite-muscovite porphyritic granodiorite and minor tonalite" New Hampshire Plutonic Suite Northeast Kingdom batholith Derby pluton granodiorite and tonalite Plutonic Devonian Ddrz Ddrz 0 73 60 0 25 bedrock granodiorite Rim zone of granodiorite New Hampshire Plutonic Suite Northeast Kingdom batholith Derby pluton granodiorite Plutonic Devonian Debg Debg 0 36 30 0 26 bedrock granodiorite granite "Light-gray to pink, medium- to coarse-grained, massive, seriate to porphyritic granodiorite and granite" New Hampshire Plutonic Suite Northeast Kingdom batholith Echo Pond pluton granodiorite and tonalite Plutonic Devonian Dedg Dedg 0 45 38 0 27 bedrock gabbro diorite Outer zone of quartz gabbro and quartz diorite New Hampshire Plutonic Suite Northeast Kingdom batholith Echo Pond pluton gabbro and quartz diorite Plutonic Devonian Degr Degr 0 55 45 0 28 bedrock granite Inner zone of granite New Hampshire Plutonic Suite Northeast Kingdom batholith Echo Pond pluton granite Plutonic Devonian simplified description Dfpg Dfpg 0 82 68 0 462 bedrock granite "Pink to gray, nonfoliated, porphyritic to coarse-grained biotite granite, phenocrysts of potassium feldspar are as large as 2 by 3 cm" Bronson Hill anticlinorium or arch Bronson Hill arch intrusive rocks French Pond Granite Plutonic Late Devonian simplified description Dfqm Dfqm 40 40 20 0 464 bedrock quartz monzonite granite "Greenish-gray, pink-tinged, weakly foliated, coarse-grained to porphyritic biotite granite of the Fairlee pluton" Bronson Hill anticlinorium or arch Bronson Hill arch intrusive rocks Fairlee Quartz Monzonite Metaplutonic Early Devonian simplified description Dg Dg 0 91 76 0 49 bedrock granite trondhjemite "Garnet-muscovite-biotite granodiorite, muscovite-rich quartz monzonite and granodiorite, granite pegmatite, and aplite" New Hampshire Plutonic Suite Devonian granitic rocks of southern Vermont Granite and trondhjemite dikes of Chester and Athens domes and W of CVT granite and trondhjemite dikes Plutonic Devonian Dga Dga 70 8 70 0 424 bedrock amphibolite granofels "Hornblende amphibolite and hornblende-plagioclase-quartz granofels, interpreted as metabasaltic and volcaniclastic rocks" Connecticut Valley Trough Connecticut Valley Trough Gile Mountain Formation Amphibolite member Metavolcanic Lower Devonian simplified description Dgm Dgm 37 19 12 0 418 bedrock slate metasandstone "Dark-gray slate and phyllite containing sparse to moderately abundant beds of light-gray, fine-grained metasandstone and metasiltstone, 1 mm to 1 cm thick " Connecticut Valley Trough Connecticut Valley Trough Gile Mountain Formation Meetinghouse Slate Member Metasedimentary Lower Devonian Dgmc Dgmc 60 60 0 0 421 bedrock conglomerate "Thin lens of metadiamictite with abundant dark-gray, pyritic, and calcareous metapelite matrix at the base of the Meetinghouse Slate Member (Dgm), south of Bradford" Connecticut Valley Trough Connecticut Valley Trough Gile Mountain Formation Quartz-pebble metaconglomerate member Metasedimentary Lower Devonian simplified description Dgmg Dgmg 70 70 0 0 420.5 bedrock granofels grit "Lenticular masses of metamorphosed quartose volcaniclastic grit and conglomerate, commonly having abundant dark-gray pelitic matrix interlayered with sandstone, pelite, and porphyritic rhyolite (Dgmr)" Connecticut Valley Trough Connecticut Valley Trough Gile Mountain Formation Grit Metasedimentary / Metavolcanic Lower Devonian simplified description Dgmr Dgmr 62 72 32 0 420 bedrock metarhyolite "Very light gray, fine-grained porphyritic metafelsite schist or granofels. Groundmass recrystallized to an aggregate of quartz, microcline, plagioclase, biotite, muscovite, and apatite. Relict phenocrysts of quartz, microcline, and plagioclase" Connecticut Valley Trough Connecticut Valley Trough Gile Mountain Formation Felsic metavolcanic member Metavolcanic Lower Devonian Dgq Dgq 29 27 9 0 423 bedrock quartzite "Brown to gray, noncarbonaceous quartz-mica schist and feldspathic quartzite in beds 50 cm to 5 m thick, gradational to Dgqs through interbedding of phyllite beds and decrease in thickness of quartzite beds" Connecticut Valley Trough Connecticut Valley Trough Gile Mountain Formation Thick-bedded micaceous feldspathic quartzite member Metasedimentary Lower Devonian Dgqs Dgqs 30 20 0 0 417 bedrock quartzite phyllite "Gray to light-gray, fine-grained, micaceous quartzite a few cm to tens of cm thick, interbedded with dark-gray, graphitic slate, phyllite, or schist" Connecticut Valley Trough Connecticut Valley Trough Gile Mountain Formation Quartzite and metapelite member Metasedimentary Lower Devonian simplified description Dgr Dgr 30 13 0 0 422 bedrock schist quartzite "Light- to medium-gray, fine-grained micaceous quartzite to dark-gray muscovite-quartz-biotite carbonaceous phyllite or schist in beds 10 to 25 cm thick, and dark-gray micaceous phyllite or schist containing beds of micaceous quartzite, locally thickly bedded" Connecticut Valley Trough Connecticut Valley Trough Gile Mountain Formation Rhythmically graded member Metasedimentary / Metavolcanic Lower Devonian Dhg Dhg 0 99 50 0 45 bedrock granite tonalite "Porphyritic, light-gray, hypabyssal biotite granite and tonalite in sill-like bodies - Contains phenocrysts of euhedral and embayed quartz, euhedral microcline with Carlsbad twinning (in granite), plagioclase, and euhedral biotite (+/-muscovite)" New Hampshire Plutonic Suite Other plutons of the New Hampshire Plutonic Suite Granite and tonalite in sill-like bodies granite and tonalite Plutonic Devonian simplified description Di Di 27 26 12 0 427 bedrock slate metasandstone "Medium-dark-gray to grayish-black lustrous slate, phyllite, and schist containing sparse to moderately abundant 1-mm to 5-cm-thick beds of light-gray, fine-grained metasandstone and metasiltstone, commonly pyritiferous and calcareous" Connecticut Valley Trough Connecticut Valley Trough Ironbound Mountain Formation "Slate, phyllite, and schist member" Metasedimentary Lower Devonian Dia Dia 70 8 70 0 430 bedrock amphibolite granofels "Hornblende amphibolite and hornblende-plagioclase-quartz granofels, interpreted as metabasalt and mafic volcaniclastic rock" Connecticut Valley Trough Connecticut Valley Trough Ironbound Mountain Formation Amphibolite member Metavolcanic Lower Devonian simplified description Dih Dih 47 47 12 0 428 bedrock metawacke conglomerate "Lenticular masses of coarse-grained quartzose volcaniclastic grit and cobble metaconglomerate commonly with abundant dark-gray metapelitic matrix (diamictite) interlayered with metasandstone, metapelite, and porphyritic metarhyolite" Connecticut Valley Trough Connecticut Valley Trough Ironbound Mountain Formation Halls Stream Grit Member Metasedimentary / Metavolcanic Lower Devonian simplified description Dir Dir 37 45 15 0 431 bedrock metasandstone slate "Light- to medium-gray, fine-grained micaceous metasandstones that grade upward into subordinate dark-gray slate or phyllite, some rocks are calcareous" Connecticut Valley Trough Connecticut Valley Trough Ironbound Mountain Formation Rhythmically graded member Metasedimentary Lower Devonian Dkbg Dkbg 0 36 30 0 41 bedrock granite "Light-gray, medium-grained quartz-rich, biotite-muscovite granite. Has distinctly more potassium feldspar and is lighter gray than rocks of the East Barre plutons" New Hampshire Plutonic Suite Other plutons of the New Hampshire Plutonic Suite Knox Mountain pluton biotite-muscovite granite Plutonic Devonian simplified description Dkq Dkq 42 25 18 0 463.5 bedrock quartz monzonite granodiorite "Medium- to coarse-grained, potassium-feldspar-megacrystic, biotite granodiorite gneiss of the Ashuelot pluton" Bronson Hill anticlinorium or arch Bronson Hill arch intrusive rocks Kinsman Quartz Monzonite Metaplutonic Early Devonian Dl Dl 40 40 8 0 469 bedrock slate quartzite "Medium-dark- to dark-gray slate interlayered with light-gray, fine-grained micaceous quartzite, in southeastern Vermont near the Vernon dome Dl is equated with DSwb and may be older than in Bradford area" Bronson Hill anticlinorium or arch Bronson Hill arch intrusive rocks Littleton Formation Gray slate and quartzite member Metasedimentary Lower Devonian Dla Dla 64 51 18 0 471 bedrock greenstone Metamorphosed mafic volcanic rocks Bronson Hill anticlinorium or arch Bronson Hill arch intrusive rocks Littleton Formation Metamorphosed mafic volcanic rocks member Metavolcanic Lower Devonian simplified description Dlr Dlr 50 40 0 0 470 bedrock metafelsite granofels "White-weathering, medium- to dark-gray, foliated and laminated, aphanitic to very fine grained granofels to schist or metatuff, welded tuff, and lithic tuff commonly with a few percent mm-size quartz and microcline phenocrysts" Bronson Hill anticlinorium or arch Bronson Hill arch intrusive rocks Littleton Formation Metarhyolite member Metavolcanic Lower Devonian Dm Dm 25 25 0 0 464.2 bedrock diorite "Dark-gray, medium-grained metadiorite composed mainly of secondary minerals such as saussuritized plagioclase, amphibole, epidote, chlorite, and calcite" Bronson Hill anticlinorium or arch Bronson Hill arch intrusive rocks Moulton Diorite Metaplutonic Early Devonian Dmbg Dmbg 0 36 30 0 39 bedrock granite "Almost-white to dark-gray, locally pink, medium- to coarse-grained hypidiomorphic, granular, biotite-muscovite-microcline-plagioclase granite; accessories include apatite, sphene, pyrite, and magnetite" New Hampshire Plutonic Suite Northeast Kingdom batholith Maidstone pluton granite Plutonic Devonian Dnbg Dnbg 0 45 38 0 37 bedrock granite "Pinkish gray to cream-colored, medium- to coarse-grained, magnetite-microcline-perthite-biotite granite" New Hampshire Plutonic Suite Northeast Kingdom batholith Newark pluton granite Plutonic Devonian simplified description Dniz Dniz 0 45 38 0 32 bedrock monzodiorite granodiorite "Gray, medium- to coarse-grained, massive, biotite-clotted, hornblende-quartz monzodiorite, minor granodiorite, and granite divided into a western zone (Dnwz), inner zone (Dniz), and core of quartz monzonite (Dnqm)" New Hampshire Plutonic Suite Northeast Kingdom batholith Nulhegan pluton inner zone Plutonic Devonian simplified description Dnqm Dnqm 0 45 38 0 30 bedrock monzonite monzodiorite "Gray, medium- to coarse-grained, massive, biotite-clotted, hornblende-quartz monzodiorite, minor granodiorite, and granite divided into a western zone (Dnwz), inner zone (Dniz), and core of quartz monzonite (Dnqm)" New Hampshire Plutonic Suite Northeast Kingdom batholith Nulhegan pluton main zone Plutonic Devonian simplified description Dnwz Dnwz 0 45 38 0 31 bedrock monzodiorite granodiorite "Gray, medium- to coarse-grained, massive, biotite-clotted, hornblende-quartz monzodiorite, minor granodiorite, and granite divided into a western zone (Dnwz), inner zone (Dniz), and core of quartz monzonite (Dnqm)" New Hampshire Plutonic Suite Northeast Kingdom batholith Nulhegan pluton western zone Plutonic Devonian simplified description Dr Dr 54 44 16 0 464.4 bedrock metarhyolite Dikes and sills of porphyritic and nonporphyritic metarhyolite of Hunt Mountain intrusive into the Albee Formation. Some contain xenoliths of the Comerford Intrusive Complex (Scd) Bronson Hill anticlinorium or arch Bronson Hill arch intrusive rocks dikes and sills Metaplutonic Early Devonian DSfr DSfr 30 20 8 0 432 bedrock metasandstone slate "Thick-bedded, ankeritic, micaceous, and feldspathic metasandstones interlayered with subordinate dark-gray metapelite. Metasandstone beds are rusty weathering and up to 4 m thick, calc-silicate lenses locally present" Connecticut Valley Trough Connecticut Valley Trough Frontenac Formation Metasandstone and metapelite member Metasedimentary Devonian and Silurian DSfra DSfra 70 8 70 0 433 bedrock amphibolite Garnetiferous hornblende schist and minor hornblende amphibolite Connecticut Valley Trough Connecticut Valley Trough Frontenac Formation Amphibolite member Metavolcanic Devonian and Silurian Dst Dst 0 81 68 0 44 bedrock tonalite "Gray, medium-grained, nonfoliated biotite-muscovite tonalite" New Hampshire Plutonic Suite Other plutons of the New Hampshire Plutonic Suite Stiles Pond pluton tonalite Plutonic Devonian DSw DSw 20 8 0 0 447 bedrock phyllite metalimestone "Dark-gray to silvery-gray, lustrous, carbonaceous muscovite-biotite-quartz (+/-garnet) phyllite containing abundant beds of punky-brown-weathering, dark-bluish-gray micaceous quartz-rich limestone in beds ranging from 10 cm to 10 m thick" Connecticut Valley Trough Connecticut Valley Trough Waits River Formation Carbonaceous phyllite and limestone member Metasedimentary Lower Devonian and Upper Silurian DSwa DSwa 70 8 70 0 439 bedrock amphibolite greenstone "Massive, coarse-grained hornblende-plagioclase gneiss and granofels, finely foliated hornblende plagioclase amphibolite, and actinolite-epidote-chlorite greenstone" Connecticut Valley Trough Connecticut Valley Trough Waits River Formation Mafic member Metavolcanic Lower Devonian and Upper Silurian DSwac DSwac 20 20 0 0 444 bedrock metasandstone metalimestone "Gray- to bluish-gray, fine- to medium-grained, thinly bedded calcareous metasandstone, quartzose metalimestone, and fissile, laminated calcareous metasandstone and phyllite" Connecticut Valley Trough Connecticut Valley Trough Waits River Formation Ayers Cliff Member Metasedimentary Lower Devonian and Upper Silurian simplified description DSwb DSwb 40 13 0 0 434 bedrock schist metawacke "Dark-gray to coaly-black, fine-grained plagioclase-muscovite-quartz schist and metawacke, shown southeast of Springfield, in part correlative with staurolite-grade rocks mapped as Littleton Formation" Connecticut Valley Trough Connecticut Valley Trough Waits River Formation Muscovite porphyroblastic carbonaceous schist member Metasedimentary Lower Devonian and Upper Silurian simplified description DSwb/Dl DSwb/Dl 40 13 0 0 435 bedrock schist metawacke "Dark-gray to coaly-black, fine-grained plagioclase-muscovite-quartz schist and metawacke, shown southeast of Springfield, in part correlative with staurolite-grade rocks mapped as Littleton Formation" Connecticut Valley Trough Connecticut Valley Trough Waits River or Littleton Formation Muscovite porphyroblastic carbonaceous schist member Metasedimentary Lower Devonian and Upper Silurian DSwc DSwc 27 54 21 0 441 bedrock quartzite "Gray quartzite and feldspathic quartzite, in part volcaniclastic and locally interbedded with amphibolite" Connecticut Valley Trough Connecticut Valley Trough Waits River Formation Crow Hill Member Metasedimentary / Metavolcanic Lower Devonian and Upper Silurian simplified description DSwf DSwf 40 8 13 0 437 bedrock metafelsite schist "Light-gray to grayish-green, chlorite-biotite-muscovite-plagioclase-quartz schist and fragmental quartz-plagioclase granofels or metatuff" Connecticut Valley Trough Connecticut Valley Trough Waits River Formation Felsic volcanic member Metavolcanic Lower Devonian and Upper Silurian DSwgs DSwgs 37 36 25 0 438 bedrock schist "Rusty-brown to silvery-gray, coarse-grained garnet (large)-muscovite-biotite-hornblende schist and hornblende-fascicule schist" Connecticut Valley Trough Connecticut Valley Trough Waits River Formation Garbenschiefer member Metasedimentary / Metavolcanic Lower Devonian and Upper Silurian DSwi DSwi 40 60 30 0 445 bedrock conglomerate "Gray- to bluish-gray polymict limestone metaconglomerate containing pebbles to cobbles of limestone, pelite, granite, and intermediate to felsic volcanic rocks, also locally occurs in the Northfield Formation" Connecticut Valley Trough Connecticut Valley Trough Waits River Formation Irasburg Conglomerate Metasedimentary Lower Devonian and Upper Silurian DSwq DSwq 27 54 21 0 442 bedrock quartzite "Light-gray to tan, thinly bedded quartzite in beds 2 cm to 10 cm thick, exposed north of the Chester dome and south of Springfield, contains detrital zircon having Grenvillian provenance" Connecticut Valley Trough Connecticut Valley Trough Waits River Formation Quartzite and feldspathic quartzite member Metasedimentary Lower Devonian and Upper Silurian simplified description DSwqc DSwqc 30 100 20 0 443 bedrock schist conglomerate "Light-gray, muscovite-quartz schist and quartz conglomerate and dark-gray carbonaceous, polymict schistose quartz conglomerate" Connecticut Valley Trough Connecticut Valley Trough Waits River Formation Quartz-cobble and schistose metaconglomerate member Metasedimentary Lower Devonian and Upper Silurian simplified description DSws DSws 41 28 16 0 436 bedrock slate quartzite "Predominantly dark- to light-gray, lustrous, carbonaceous chlorite-biotite-muscovite-quartz slate, phyllite, or schist, contains thin beds of quartzite and only sparse layers of punky weathering limestone" Connecticut Valley Trough Connecticut Valley Trough Waits River Formation Slate and phyllite member Metasedimentary Lower Devonian and Upper Silurian DSwt DSwt 33 23 12 0 446 bedrock phyllite granofels Carbonaceous phyllite containing meter-thick beds of calcareous granofels. Unit occurs only in Massachusetts Connecticut Valley Trough Connecticut Valley Trough Waits River Formation Calcareous granofels member Metasedimentary Lower Devonian and Upper Silurian DSwv DSwv 50 20 13 0 440 bedrock schist granofels "Silvery-grayish-green to light-gray, muscovite-biotite (chlorite)-plagioclase-quartz schist and granofels" Connecticut Valley Trough Connecticut Valley Trough Waits River Formation Volcaniclastic rock member Metasedimentary / Metavolcanic Lower Devonian and Upper Silurian Dvbg Dvbg 0 45 38 0 38 bedrock granite tonalite "A western zone of medium to fine-grained, biotite-muscovite granite and minor hornblende-biotite tonalite and an eastern, more melanocratic zone of biotite-hornblende quartz monzonite like that in the Nulhegan pluton, and biotite granodiorite" New Hampshire Plutonic Suite Northeast Kingdom batholith Victory pluton granite tonalite and monzonite Plutonic Devonian Dwdg Dwdg 0 55 45 0 29 bedrock gabbro diorite "Dark-gray, medium- to coarse-grained, massive, quartz-biotite-hornblende (+/-pyroxene) gabbro and diorite" New Hampshire Plutonic Suite Northeast Kingdom batholith West Charleston pluton gabbro and diorite Plutonic Devonian simplified description Dwhz Dwhz 0 73 60 0 35 bedrock granite altered granite "Light-gray to pink, medium- to very coarse-grained, massive, miarolitic garnet-muscovite peraluminous leucogranite. Varies from a pegmatitic main zone (Dwmz) to biotitic granodioritic western zone (Dwwz) to inner hydrothermally altered zone (Dwhz)" New Hampshire Plutonic Suite Northeast Kingdom batholith Willoughby pluton hydrothermally altered zone Plutonic Devonian simplified description Dwmz Dwmz 0 36 30 0 33 bedrock granite pegmatite "Light-gray to pink, medium- to very coarse-grained, massive, miarolitic garnet-muscovite peraluminous leucogranite. Varies from a pegmatitic main zone (Dwmz) to biotitic granodioritic western zone (Dwwz) to inner hydrothermally altered zone (Dwhz)" New Hampshire Plutonic Suite Northeast Kingdom batholith Willoughby pluton main zone Plutonic Devonian simplified description Dwwz Dwwz 0 45 38 0 34 bedrock granodiorite "Light-gray to pink, medium- to very coarse-grained, massive, miarolitic garnet-muscovite peraluminous leucogranite. Varies from a pegmatitic main zone (Dwmz) to biotitic granodioritic western zone (Dwwz) to inner hydrothermally altered zone (Dwhz)" New Hampshire Plutonic Suite Northeast Kingdom batholith Willoughby pluton western zone Plutonic Devonian dikes as arcs only Jd Jd 70 100 0 0 19 bedrock granite syenite "Dikes of granite, syenite, quartz bostonite, camptonite, aplite, and pegmatite" White Mountain Igneous Suite Monadnock Mountain pluton dikes Plutonic Middle Jurrassic simplified description Jme Jme 40 8 30 0 17 bedrock gabbro essexite Pyroxene-biotite-hornblende andesine gabbroic rock grading into quartz syenite White Mountain Igneous Suite Monadnock Mountain pluton essexite Plutonic Middle Jurrassic simplified description Jmg Jmg 40 0 40 0 18 bedrock granite syenite "Hornblende-biotite microperthite granite, gradational into quartz syenite" White Mountain Igneous Suite Monadnock Mountain pluton granite Plutonic Middle Jurrassic simplified description Jmsy Jmsy 20 0 30 0 16 bedrock syenite Greenish-gray to pink hornblende-biotite quartz syenite White Mountain Igneous Suite Monadnock Mountain pluton quartz syenite Plutonic Middle Jurrassic simplified description Kab Kab 5 8 30 0 5 bedrock andesite breccia Andesite breccia containing xenoliths of Mesoproterozoic gneiss and autoclasts of felsic alkalic and fine-grained mafic rocks White Mountain Igneous Suite Cuttingsville stock andesite breccia Volcanic Early Cretaceous simplified description Kag Kag 54 16 44 0 6 bedrock granite Medium- to coarse-grained biotite microperthite-orthoclase-albite granite White Mountain Igneous Suite Ascutney Mountain stock granite Plutonic Early Cretaceous simplified description Kahg Kahg 58 22 28 0 7 bedrock granite Hornblende granite occurring as small intrusive masses in Kas White Mountain Igneous Suite Ascutney Mountain stock hornblende granite Plutonic Early Cretaceous simplified description Kas Kas 40 8 40 0 8 bedrock syenite "Syenite-porphyrite to sericite-perthite-hornblende-biotite-syenite, contains minor fayalite, augite and quartz, occurs as a partial ring dike in the Little Ascutney stock" White Mountain Igneous Suite Ascutney Mountain stock syenite Plutonic Early Cretaceous simplified description Kav Kav 40 20 24 0 9 bedrock trachyte breccia "Trachytic to rhyolitic tuffs, and breccias containing fragments of volcanic rocks having trachytic flow structure and layering. Interpreted as volcanic rocks of the edifice" White Mountain Igneous Suite Ascutney Mountain stock tuffs Volcanic Early Cretaceous simplified description Kbh Kbh 58 24 38 0 14 bedrock syenite "A small 0.5 km long, NW trending stock consisting of a coarse-grained alkali syenite core, a fine-grained quartz syenite border, and associated trachyte dikes (Kfd)" White Mountain Igneous Suite Barber Hill stock syenite Plutonic Early Cretaceous simplified description Kes Kes 40 0 20 0 4 bedrock gabbro essexite Essexite (alkali gabbro) White Mountain Igneous Suite Cuttingsville stock essexite Plutonic Early Cretaceous simplified description Kfd Kfd 100 70 0 0 15 bedrock trachyte trachyte dikes White Mountain Igneous Suite Barber Hill stock trachyte dike Plutonic Early Cretaceous simplified description Kgd Kgd 44 22 44 0 11 bedrock gabbro diorite Medium- to coarse-grained augite-hornblende-biotite gabbro infiltrated by hornblende and biotite diorite White Mountain Igneous Suite Little Ascutney stock gabbro and diorite Plutonic Early Cretaceous simplified description Khf Khf 44 12 52 0 10 bedrock hornfels Dense compact hornfels consisting of recognizable but altered schists of the country rock only shown around main Ascutney Mountain stock White Mountain Igneous Suite Ascutney Mountain stock hornfels Metasedimentary Early Cretaceous "dikes as arcs only, simplified description" Kmd Kmd 100 72 0 6 20 bedrock diabase lamprophyre "Predominantly mafic and intermediate dikes of diabase, olivine-augite diabase, lamprophyre, calcite amygdaloidal mafic dikes, alkali basalt, monchiquite and granitic, rhyolite, trachyte and foidal felsic dikes and spherulitic trachyte dikes" White Mountain Igneous Suite mafic and intermediate dikes dikes Plutonic Middle Jurrassic to Early Cretaceous simplified description Kns Kns 30 8 30 0 2 bedrock syenite hornblende syenite "Nepheline and sodalite syenite, hornblende syenite" White Mountain Igneous Suite Cuttingsville stock syenite Plutonic Early Cretaceous simplified description Kpd Kpd 70 100 0 0 12 bedrock paisanite syenite Fine-grained syenitic dike similar to spherulitic dikes found within the plutons and in the adjacent country rocks White Mountain Igneous Suite Ascutney Mountain stock paisanite dike Plutonic Early Cretaceous simplified description Kqs Kqs 44 10 34 0 3 bedrock syenite Quartz syenite White Mountain Igneous Suite Cuttingsville stock quartz syenite Plutonic Early Cretaceous simplified description ls ls 85 29 19 0 332 bedrock limestone "Pods, lenses or zones of thinly bedded limestone and limestone conglomerate" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Bull West Castleton and Hatch Hill Formations limestone member Metasedimentary Cambrian and Neoproterozoic? null null Dbg 0 0 0 0 40 bedrock granite hornfels "Shows areas of intricately mixed country rock, hornfels, and abundant dikes and sills of granite. Underlying color and symbol identify country rock unit" New Hampshire Plutonic Suite Northeast Kingdom batholith mixed country rock hornfels dikes and sills of granite overprint pattern Mixed Devonian and older purple hash overprint sub_lith only null null Scd 0 0 0 0 457 bedrock mafic dikes "Abundant, foliated to weakly foliated, metatholeiitic mafic dikes, some sheeted. Shown as overprint" Lake Memphremagog Intrusive Suite Comerford Intrusive Complex Mafic dikes Metaplutonic Late Silurian simplified description Oa Oa 0 20 20 0 480 bedrock metavolcanics "Heterogeneous unit of metamorphosed volcanic, volcaniclastic, and sedimentary rocks dominated by tuff to tuff-breccia of basalt to sodic rhyolite. Sedimentary protoliths include gray sulfidic shale, ironstone, siltstone, graywacke, volcanic conglomerate, and rare limestone" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Ammonoosuc Volcanics Undivided Metavolcanic Upper and Middle Ordovician Oaa Oaa 0 50 13 0 482 bedrock meta-andesite meta-basalt "Dark-greenish-gray to medium-bluish-gray metamorphosed andesitic and basaltic tuff, crystal tuff, and tuff breccia, minor pillow lava. Commonly contains plagioclase and (or) altered mafic phenocrysts" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Ammonoosuc Volcanics Meta-andesitic and metabasaltic tuff member Metavolcanic Upper and Middle Ordovician Oac Oac 25 60 9 0 485.5 bedrock dolomite phyllite Siliceous and argillaceous dolomite and calcareous pelite Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Ammonoosuc Volcanics Dolomite and pelite member Metasedimentary / Metavolcanic Upper and Middle Ordovician simplified description Oag Oag 12 47 15 0 323.5 bedrock wacke slate "Light-gray, tan weathering, mica-speckled, massive to thin-bedded quartz-plagioclase wacke interbedded with dark gray carbonaceous slate. Conatins autoclastic chips of gray slate, fragments of volcanics and clasts of gray quartz and oligoclase" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Austin Glen Graywacke Metasedimentary Upper Ordovician Oam Oam 12 53 11 0 485 bedrock metasiltstone phyllite "Medium-light-bluish-gray, medium-bluish-gray, medium-dark-gray, to medium-dark-greenish-gray metasiltstone and phyllite and medium-gray feldspathic metawacke. Purple tinge common, coticule and magnetite locally abundant" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Ammonoosuc Volcanics "Metasiltstone, phyllite and metawacke member" Metasedimentary / Metavolcanic Upper and Middle Ordovician Oap Oap 0 70 13 0 486 bedrock slate phyllite "Dark-gray to grayish-black, rusty-weathering, sulfidic slate and phyllite interlayered with felsic tuffs and minor sandy rocks, locally forms the base of the Ammonoosuc Volcanics" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Ammonoosuc Volcanics Sulfidic slate and phyllite member Metasedimentary / Metavolcanic Upper and Middle Ordovician simplified description Oar Oar 8 60 20 0 481 bedrock metafelsite "Greenish-gray, light-bluish-gray, or medium-bluish-gray metarhyolite tuff, lapilli tuff, tuff breccia, and lava. Generally porphyritic with 5 to 20 percent plagioclase and, in some places, quartz phenocrysts" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Ammonoosuc Volcanics Metarhyolite tuff member Metavolcanic Upper and Middle Ordovician Oarq Oarq 0 30 0 0 483 bedrock metarhyolite metafelsite "Coarsely porphyritic, greenish-gray, light-bluish-gray, or medium-bluish-gray metarhyolite tuff, lapilli tuff, and tuff breccia. Quartz and plagioclase phenocrysts commonly as large as 5 mm" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Ammonoosuc Volcanics Coarsely porphyritic metarhyolite tuff member Metavolcanic Upper and Middle Ordovician Oat Oat 0 30 13 0 484 bedrock metafelsite Metamorphosed aphyric rhyolite tuff Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Ammonoosuc Volcanics Metamorphosed aphyric rhyolite tuff member Metavolcanic Upper and Middle Ordovician simplified description Ob Ob 0 30 0 0 108 bedrock dolostone limestone Interbedded orangey-tan to buff-weathering dolostone and bluish-gray to gray mottled dolomitic limestone or calcite marble and calcareous sandstone Vermont Valley Sequence and Middlebury Synclinorium Bascom Formation Sedimentary Middle and Lower Ordovician Obku Obku 20 20 8 0 61 bedrock limestone dolostone "Gray limestones, fossiliferous limestones, and dolostones" Adirondack lowlands and Lake Champlain lowlands Beekmantown Group Beekmantown Group undivided Sedimentary Middle Ordovician to Upper Cambrian Obqd Obqd 24 40 20 0 465 bedrock quartz diorite trondhjemite "Light-gray, well-foliated subporphyritic biotite (+/-hornblende)-quartz diorite and trondhjemite gneiss, forms sills in overlying Ammonoosuc Volcanics" Bronson Hill anticlinorium or arch Bronson Hill arch intrusive rocks Biotite quartz diorite gneiss of Vernon dome Metaplutonic Late Ordovician Obr Obr 8 17 10 0 55 bedrock dolostone limestone "Thin-bedded to massive dolostone, sandy dolostone, and light-gray limestone, vertical burrows in basal beds, upper beds fossiliferous with black chert" Adirondack lowlands and Lake Champlain lowlands Black River Group Black River Group undivided Sedimentary Upper Ordovician Obvb Obvb 27 88 17 0 322.5 bedrock breccia basalt Vesicular basalt igneous breccia in the Walloomsac Formation perhaps intrusive The Taconic Allochthon The Taconic Allochthon Walloomsac Formation Vesicular basalt igneous breccia Metavolcanic Upper Ordovician simplified description OCal OCal 8 8 13 0 489 bedrock schist granofels "Light-gray to greenish-gray, white-weathering, fine-grained feldspathic metasandstone and metasiltstone, and light-gray to greenish-gray to dark-gray phyllite. Lesser amounts of quartzite. Rare calc-silicate nodules. Locally sulfidic. Pinstriping is common" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Albee Formation Metasandstone and metasiltstone member Metasedimentary / Metavolcanic Ordovician and Cambrian OCali OCali 37 45 69 0 491 bedrock ironstone coticule "Ironstone, magnetite-rich rock and coticule" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Albee Formation Iron formation member Metasedimentary / Metavolcanic Ordovician and Cambrian overprint pattern OCalm OCalm 8 8 13 0 492 bedrock magnetite Magnetite-rich areas in Albee Formation OCal shown as overprint Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Albee Formation Magnetite-rich areas Metasedimentary Ordovician and Cambrian OCalp OCalp 17 34 71 0 490 bedrock slate phyllite "Commonly sulfidic and rusty weathering. Indistinguishable from the Scarritt Member, but crops out in small areas" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Albee Formation Slate and phyllite member Metasedimentary Ordovician and Cambrian simplified description OCals OCals 13 21 37 0 493 bedrock slate phyllite "Dark-gray slate interlayered with thin beds of light-gray, fine-grained micaceous and feldspathic metasandstone" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Albee Formation Scarrritt Member Metasedimentary Ordovician and Cambrian Ocbe Ocbe 8 34 12 0 105 bedrock limestone dolostone "Light-gray to creamy-white-weathering fine grained limestone, orangey-buff-weathering dolostone, and reddish streaked (hematite) calcite marble" Vermont Valley Sequence and Middlebury Synclinorium ? Chipman Formation Beldens Member Sedimentary Middle Ordovician simplified description Ocbrp Ocbrp 8 34 12 0 104 bedrock dolostone limestone "Thickly bedded, beeswax-scored, orangey-beige-weathering, yellowish-gray to light-bluish-gray dolostone, dark-gray dolostone and minor beds of bluish-gray limestone. Transitions to Beldens Mbr.. Equivalent to Providence Island Dolostone (Ofcpi)" Vermont Valley Sequence and Middlebury Synclinorium ? Chipman Formation Bridport Member Sedimentary Middle Ordovician Ocbu Ocbu 12 53 11 0 106 bedrock limestone Light-bluish-gray mottled dolomitic limestone Vermont Valley Sequence and Middlebury Synclinorium Chipman Formation Buchards Member Sedimentary Middle Ordovician OCg OCg 12 23 16 0 151 bedrock dolostone breccia "Dolomite and dolomite breccia composed of angular clasts of dolostone, sandstone, and chert in buff to gray quartzose dolostone" Cover rocks of the Saint Albans area Gorge Formation Sedimentary Lower Ordovician and Cambrian Ocgu Ocgu 14 24 6 0 57 bedrock limestone calcareous sandstone "Dark- to light-gray, massively bedded fossiliferous limestone and calcareous sandstone" Adirondack lowlands and Lake Champlain lowlands Chazy Group Chazy Group undivided Sedimentary Upper and Middle Ordovician Och Och 13 40 30 0 387 bedrock schist quartzite "Rusty-grayish-brown-weathering, locally splintery-fractured, dark-gray to steel-gray biotite-quartz-feldspathic schist and quartzite and interbedded carbonaceous, small-garnet papery muscovite phyllite and schist similar to Ochs" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Cram Hill Formation Gray quartz schist member Metasedimentary Middle? and Early Ordovician Ocha Ocha 100 15 100 0 385 bedrock amphibolite greenstone "Light-greenish-gray, feldspathic chlorite-actinolite greenstone and bedded andesitic to basaltic tuff and amphibolite, associated with ironstone, coticule, and minor pods of dolostone" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Cram Hill Formation Amphibolite and greenstone member Metavolcanic Middle? and Early Ordovician Ochcv Ochcv 70 13 60 0 390 bedrock greenstone "Light-green, fine- to medium-grained, massive carbonate-biotite-quartz-sphene-chlorite-actinolite-epidote greenstone with deformed pillows, interfingers with the Umbrella Hill Conglomerate Member (Ochuc) and with phyllite-chip conglomerate (Ochsb)" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Cram Hill Formation of the Newport Center area Coburn Hill Metabasalt Member Metavolcanic Middle? and Early Ordovician Ochd Ochd 0 50 8 0 53 bedrock limestone shale "Interbedded graded bioclastic limestone, bluish-gray calcareous shale, and laminated shale" Adirondack lowlands and Lake Champlain lowlands Trenton Group Cumberland Head Formation Sedimentary Upper Ordovician Ochfg Ochfg 20 29 29 0 380 bedrock granofels greenstone "Dark-medium-gray biotite-plagioclase-quartz granofels and and grayish-green chlorite-plagioclase-quartz granofels, contains thin layers of ankerite-epidote greenstone, ankerite-spotted feldspathic granofels, and coticule. Locally hornblende rich at higher metamorphic grade" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Cram Hill Formation Granofels member Metasedimentary Middle? and Early Ordovician Ochfs Ochfs 15 45 16 0 381 bedrock schist granofels "Medium-dark-gray to dark-gray, rusty-weathering garnet-biotite-muscovite-quartz-plagioclase schist and granofels, has coarse spangles of muscovite and locally is kyanite-rich" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Cram Hill Formation Feldspathic schist and granofels member Metasedimentary Middle? and Early Ordovician simplified description Ochfv Ochfv 32 100 100 0 384 bedrock metatuff phyllite "Light-gray to whitish-gray, fine-grained sericite-quartz-phenocrystic phyllitic metatuff and whitish pyritiferous soda-rhyolite metatuff" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Cram Hill Formation Felsic volcanic member Metavolcanic Middle? and Early Ordovician simplified description Ochic Ochic 16 78 34 0 382 bedrock ironstone quartzite "Dark-gray- to sooty-black-weathering siliceous ironstone, magnetite quartzite, garnet quartzite, rusty weathering amphibolite, coticule, and pods of orangey-gray to pinkish-gray-weathering dolostone" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Cram Hill Formation "Ironstone, quartzite, and coticule member" Metasedimentary / Metavolcanic Middle? and Early Ordovician Ochp Ochp 20 59 31 0 391 bedrock phyllite granofels "Gray to silvery-green, sericite-chlorite-quartz phyllite with thin beds of rusty-weathering, pearly-white, fine-grained granofels. Interlayered with Ochuc and Ochsb at the contacts. Mapped locally in the Albany area" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Cram Hill Formation of the Newport Center area Phyllite member Metasedimentary Middle? and Early Ordovician simplified description Ochpq Ochpq 13 67 47 0 393 bedrock phyllite quartzite "Light-gray to tan, rusty-weathering, fine-grained quartz-sericite-chlorite-albite phyllite, quartzite, and flinty sulfidic granofels, with thin layers of felsite, conglomerate, and breccia in the vicinity of Coburn Hill" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Cram Hill Formation of the Newport Center area Phyllite and quartzite member Metasedimentary Middle? and Early Ordovician Ochq Ochq 21 74 66 0 386 bedrock conglomerate quartzite "Tan- to gray-weathering, quartz-pebble and -cobble conglomerate, feldspathic quartzite and associated slabby, rusty-weathering amphibolite and coticule" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Cram Hill Formation Quartzite and quartz-pebble conglomerate member Metasedimentary / Metavolcanic Middle? and Early Ordovician Ochs Ochs 17 75 12 0 388 bedrock schist phyllite "Light-grayish-brown- to tan-weathering, medium-dark-gray, fine-grained garnet (small)-biotite-muscovite phyllite and schist. Similar to phyllite facies (Omwh) in the Whetstone Hill Member of the Moretown Formation" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Cram Hill Formation Carbonaceous schist member Metasedimentary Middle? and Early Ordovician Ochsb Ochsb 13 40 13 0 389 bedrock phyllite conglomerate "Dark-gray, carbonaceous garnet-pyrite-sericite-chlorite-quartz phyllite with clasts of siltstone, phyllite, quartzite, and dark-gray slate breccia interbedded with Coburn Hill Metabasalt Member. Correlative with the St. Daniel Group of Quebec" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Cram Hill Formation of the Newport Center area Phyllite-chip conglomerate and slate conglomerate member Metasedimentary Middle? and Early Ordovician simplified description Ochu Ochu 19 46 11 0 379 bedrock phyllite metasiltstone "Dark-gray to grayish-green quartz-chlorite-(biotite)-muscovite phyllite, contains beds of dark-gray metasiltstone, quartzite, dark-bluish-gray vitreous quartzite, sericite phyllite (felsic tuffs), cobble to boulder conglomerate, and greenstone" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Cram Hill Formation undivided member Metasedimentary Middle? and Early Ordovician simplified description Ochuc Ochuc 27 65 35 0 392 bedrock conglomerate phyllite "Quartz-pebble and phyllitic-fragment conglomerate, and tan to gray phyllite" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Cram Hill Formation of the Newport Center area Umbrella Hill Conglomerate Member Metasedimentary Middle? and Early Ordovician simplified description Ochv Ochv 28 100 100 0 383 bedrock metadacite meta-andesite "Dark-gray and white layered metadacite and meta-andesite, gray- to tan-weathering blue-quartz phenocrystic metadacitic agglomerate, and grayish-green fragmental metadacitic and meta-andesite breccia" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Cram Hill Formation Felsic and intermediate metavolcanic member Metavolcanic Middle? and Early Ordovician Ocp Ocp 8 40 0 0 59 bedrock limestone "Gray, massively bedded fossiliferous limestone" Adirondack lowlands and Lake Champlain lowlands Chazy Group Crown Point Formation Sedimentary Middle Ordovician OCsk OCsk 7 24 16 0 153 bedrock slate dolostone "Laminated black slate with thin orange dolostone beds, includes massive dolostones mapped as Saxe Brook Formation by others in the Highgate area" Cover rocks of the Saint Albans area Skeels Corners Slate Black slate member Sedimentary Lower Ordovician and Cambrian OCskl OCskl 29 31 48 0 154 bedrock limestone sandstone "Limestone and sandstone clasts in a limestone matrix, interbedded with sandstone" Cover rocks of the Saint Albans area Skeels Corners Slate Limestone matrix conglomerate member Sedimentary Lower Ordovician and Cambrian OCsks OCsks 22 29 58 0 155 bedrock limestone sandstone Limestone and sandstone clasts in a quartz sand matrix Cover rocks of the Saint Albans area Skeels Corners Slate Sandy matrix conglomerate member Sedimentary Lower Ordovician and Cambrian OCsw OCsw 13 21 37 0 152 bedrock phyllite dolostone "Black to gray, graphitic, quartzose phyllite and schist, with tan-weathering layers and pods of gray dolostone and black quartzite" Cover rocks of the Saint Albans area Sweetsburg Formation Sedimentary Lower Ordovician and Cambrian? simplified description Ocu Ocu 15 37 19 0 109 bedrock dolostone sandstone "Gray, thinly bedded dolomitic sandstone, grading upward into dolomitic limestone or mottled dolomitic marble" Vermont Valley Sequence and Middlebury Synclinorium Cutting Dolostone Sedimentary Lower Ordovician OCw OCw 12 19 14 0 70 bedrock dolostone limestone "Predominantly light-gray and pinkish-gray, coarse-grained dolostone and cherty dolostone, containing layers of gray limestone (Ocwl)" Adirondack lowlands and Lake Champlain lowlands Beekmantown Group Whitehall Formation Sedimentary Lower Ordovician and Upper Cambrian Ocw Ocw 8 34 12 0 107 bedrock marble "Light-gray to cream-colored fine-grained calcite marble, and thin dolomitic layers, locally crossbedded, may occur as lenses at several positions within the Beldens Member" Vermont Valley Sequence and Middlebury Synclinorium Chipman Formation Weybridge Member Sedimentary Middle Ordovician OCwl OCwl 11 66 15 0 70.5 bedrock limestone Gray limestone Adirondack lowlands and Lake Champlain lowlands Beekmantown Group Whitehall Formation Sedimentary Lower Ordovician and Upper Cambrian Odp Odp 18 44 16 0 60 bedrock sandstone limestone "Gray, thin-bedded to massive sandstone and fossiliferous limestone" Adirondack lowlands and Lake Champlain lowlands Chazy Group Day Point Formation Sedimentary Middle Ordovician Ofa Ofa 13 34 18 0 66 bedrock limestone dolostone "Shown only in New York State - Medium- to dark-gray and mottled, medium- to thick-bedded dolomitic limestone and buff weathering dolostone" Adirondack lowlands and Lake Champlain lowlands Beekmantown Group Fort Ann Formation Sedimentary Lower Ordovician Ofcpi Ofcpi 8 34 12 0 62 bedrock dolostone "Shown locally from Whitehall, NY to Orwell, VT. Laterally equivalent to Providence Island Dolostone" Adirondack lowlands and Lake Champlain lowlands Beekmantown Group Fort Cassin Formation Sedimentary Middle and Lower Ordovician simplified description Ofcrp Ofcrp 26 72 17 0 63 bedrock quartzite dolostone "Light-gray, to tannish-white, well-bedded and vitreous steel-gray quartzite interbedded with orangey-tan- and beige-weathering dolostone and thin beds of fossiliferous limestone" Adirondack lowlands and Lake Champlain lowlands Beekmantown Group Fort Cassin Formation Root Pond Quartzite Member Sedimentary Lower Ordovician simplified description Ofcs Ofcs 20 22 10 0 64 bedrock limestone "Light-gray, fine-grained, and dark gray, fossiliferous, platy bluish-gray limestone. Contains upper Ibexian to lower Whiterockian conodonts at the type locality near Sciota School House, in the Benson quadrangle" Adirondack lowlands and Lake Champlain lowlands Beekmantown Group Fort Cassin Formation Scotia Limestone Member Sedimentary Midle and Lower Ordovician Ofcw Ofcw 10 26 14 0 65 bedrock calcareous siltstone quartzite "Light-tan to gray, thinly bedded and crossbedded, calcareous and dolomitic siltstone and quartzite in beds similar to the quartzite of the Root Pond Member" Adirondack lowlands and Lake Champlain lowlands Beekmantown Group Fort Cassin Formation Ward Siltstone Member Sedimentary Lower Ordovician Ofh Ofh 6 72 32 0 318 bedrock slate breccia "Black slate containing angular to irregular chips of greenish-gray to yellowish-gray slate, quartz wacke, and limestone. Interpreted by Zen (1961) as sedimentary wildflysch" The Taconic Allochthon The Taconic Allochthon Ira and Hortonville Formations Forbes Hill conglomerate and breccia Metasedimentary Upper Ordovician Ogf Ogf 8 60 0 0 54 bedrock limestone "Dark-bluish-gray-weathering, thinly bedded dark-gray to black granular limestone, locally grades upwards into sooty-weathering shaly limestone beds rich in fragments of the trilobite Cryptolithus" Adirondack lowlands and Lake Champlain lowlands Trenton Group Glens Falls Limestone Sedimentary Upper Ordovician Ogm Ogm 10 35 24 0 67 bedrock dolostone limestone "Light-gray, medium-grained, medium- to thick-bedded dolostone, locally cherty, contains lens of light-gray weathering fossiliferous limestone (Ogml)" Adirondack lowlands and Lake Champlain lowlands Beekmantown Group Great Meadows Formation Sedimentary Lower Ordovician Ogml Ogml 14 54 34 0 68 bedrock limestone Light-gray weathering fossiliferous limestone Adirondack lowlands and Lake Champlain lowlands Beekmantown Group Great Meadows Formation Sedimentary Lower Ordovician Ogmw Ogmw 12 54 42 0 69 bedrock quartzite dolostone "Tan-weathering, gray, well-bedded and crossbedded laminated quartzite and dolostone, sandy beds weather to a woody-grained surface texture" Adirondack lowlands and Lake Champlain lowlands Beekmantown Group Great Meadows Formation Winchell Creek Member Sedimentary Lower Ordovician simplified description Oh Oh 0 13 0 0 86 bedrock shale and phyllite limestone "Dark-gray siliceous shale and phyllite, containing thin beds of bluish-gray argillaceous limestone and minor beds of gray to tan quartzite, grades into limey shales of the Stony Point Formation" Vermont Valley Sequence and Middlebury Synclinorium Hortonville Formation Sedimentary Upper Ordovician Oha Oha 0 30 8 0 50 bedrock shale limestone "Clasts of limestone, dolostone, sandstone, and chert within beds of black shale and chert" Adirondack lowlands and Lake Champlain lowlands Trenton Group Hathaway Formation Sedimentary Upper Ordovician simplified description Ohc Ohc 16 73 10 0 88 bedrock conglomerate limestone Polymict limestone and dolostone-clast conglomerate Vermont Valley Sequence and Middlebury Synclinorium Hortonville Formation Sedimentary Upper Ordovician Ohg Ohg 8 30 8 0 150 bedrock limestone calcareous slate "Banded limestone and calcareous slate with local lenses of conglomerate composed of limestone, sandstone and dolostone clasts in a sandy limestone matrix" Cover rocks of the Saint Albans area Highgate Formation Sedimentary Lower Ordovician simplified description Ohi Ohi 0 13 0 0 467 bedrock granodiorite granite "Medium-greenish-gray to dark-greenish-gray, medium-grained, foliated metamorphosed granite, granodiorite, and tonalite containing quartz, microcline, saussuritized plagioclase, hornblende, biotite (chlorite alteration), and secondary calcite and sericite" Bronson Hill anticlinorium or arch Highlandcroft Plutonic Suite Bronson Hill arch intrusive rocks Highlandcroft Granodiorite Metaplutonic Late Ordovician simplified description Ohl Ohl 0 50 0 0 87 bedrock limestone "Near base (of formation) bluish-gray, granular, smooth-weathering fossiliferous limestone" Vermont Valley Sequence and Middlebury Synclinorium Hortonville Formation Sedimentary Upper Ordovician Oi Oi 0 13 0 0 90 bedrock shale and phyllite limestone "Same description as Hortonville - Dark-gray siliceous shale and phyllite, containing thin beds of bluish-gray argillaceous limestone and minor beds of gray to tan quartzite, grades into limey shales" Vermont Valley Sequence and Middlebury Synclinorium Ira Formation Sedimentary Upper Ordovician Oib Oib 0 13 0 0 51 bedrock shale siltstone Dark-gray shale with thin discontinuous beds of crossbedded and graded dolomitic siltstone Adirondack lowlands and Lake Champlain lowlands Trenton Group Iberville Formation Sedimentary Upper Ordovician Oil Oil 0 60 13 0 91 bedrock limestone Basal limestone member - locally referred to as Whipple Marble Member Vermont Valley Sequence and Middlebury Synclinorium Ira Formation Sedimentary Upper Ordovician Oilc Oilc 8 50 8 0 92 bedrock limestone conglomerate Polymict limestone conglomerate Vermont Valley Sequence and Middlebury Synclinorium Ira Formation Sedimentary Upper Ordovician simplified description Oir Oir 22 28 21 0 325 bedrock slate "Deep-maroon and bluish-green-weathering, well-bedded and variegated slate, contains minor cm-thick, white-weathering red and bluish-black cherty layers characteristic of the Mount Merino Formation. Has graptolites of C. bicornis Biozone (Berry, 1961)" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Indian River Slate Metasedimentary Upper Ordovician simplified description Oj Oj 0 73 61 0 468 bedrock tonalite "Greenish-gray to light-brownish-gray, medium-grained, weakly foliated metamorphosed tonalite. Primary minerals include quartz, plagioclase, biotite, magnetite, pyrite, and apatite; secondary minerals include chlorite, epidote, sericite, and calcite" Bronson Hill anticlinorium or arch Highlandcroft Plutonic Suite Bronson Hill arch intrusive rocks Joslin Turn Tonalite Metaplutonic Middle Ordovician simplified description Ol Ol 13 20 0 0 466 bedrock granite "Foliated biotite and (or) hornblende granite, locally diorite and lesser amounts of gabbro. Where present, potassium feldspar is microcline. Contact aureole is in the Albee Formation" Bronson Hill anticlinorium or arch Highlandcroft Plutonic Suite Bronson Hill arch intrusive rocks Lost Nation granite Metaplutonic Early Silurian to Late Ordovician Oma Oma 70 13 50 0 409 bedrock amphibolite greenstone "Includes light-pale-green chloritic ankeritic greenstone, black fine-grained hornblende plagioclase (+/-garnet+/-epidote) amphibolite, and hornblende-spotted dioritic amphibolite (Omd)" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Amphibolite and greenstone member Metavolcanic Lower Ordovician to Cambrian? simplified description Omb Omb 12 24 35 0 401 bedrock schist "Rusty-weathering, dark-gray biotite-muscovite-quartz (+/-garnet) schist, carbonaceous schist, and gray, splintery-fractured biotitic sulfidic quartz schist. Contains amphibolite, coticule, and vitreous quartzite (Ombq)" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Carbonaceous and sulfidic schist member Metasedimentary Lower Ordovician to Cambrian? Ombb Ombb 31 49 49 0 399 bedrock schist "Bluish-black, rusty weathering, fine-grained albite-sericite-chlorite-quartz schist with pyrite" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Quartz schist member Metasedimentary Lower Ordovician to Cambrian? Ombq Ombq 8 45 35 0 402 bedrock quartzite Dark-gray to steel-bluish-gray vitreous quartzite in beds as much as 10 m thick but commonly less than 1 m thick. Resembles quartzites of the Ottauquechee Formation (Cobq) Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Quartzite member Metasedimentary Lower Ordovician to Cambrian? Omc Omc 27 55 45 0 408 bedrock schist "Dark-gray, fine-grained carbonaceous biotite-muscovite-quartz (+/-garnet) phyllite and schist. Occurs west of Montpelier" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Carbonaceous schist member Metasedimentary Lower Ordovician to Cambrian? Omd Omd 70 13 50 0 409.5 bedrock amphibolite Hornblende-spotted dioritic amphibolite Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Amphibolite and greenstone member Metavolcanic Lower Ordovician to Cambrian? Omfgc Omfgc 12 34 18 0 404 bedrock granofels schist "Grayish-green, chlorite-biotite-plagioclase-quartz granofels and schist containing abundant fine layers of pinkish-gray small-garnet quartzite and coticule" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Granofels and coticule member Metasedimentary Lower Ordovician to Cambrian? Omfq Omfq 37 67 45 0 403 bedrock quartzite schist Light-grayish-brown- to tan-weathering biotite-muscovite feldspathic quartzite and muscovitic quartz schist Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Feldspathic quartzite member Metasedimentary Lower Ordovician to Cambrian? Omfs Omfs 12 27 27 0 405 bedrock schist granofels "Pale-greenish-gray, lustrous and nonlustrous chlorite-muscovite feldspathic schist and schistose granofels. Local richly garnetiferous variant (Omgt)" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Chlorite schist member Metasedimentary Lower Ordovician to Cambrian? Omfv Omfv 32 100 100 0 410 bedrock metadacite "Gray, purplish-gray, and light-gray dacitic to andesitic metavolcanic and metavolcaniclastic rocks, similar to Omwhv" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Felsic metavolcanic member Metavolcanic Lower Ordovician to Cambrian? Omgt Omgt 12 28 10 0 406 bedrock schist "Greenish-gray feldspathic garnet schist, grades into Omfs" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Garnet schist member Metasedimentary Lower Ordovician to Cambrian? Omhb Omhb 19 31 12 0 398 bedrock quartzite phyllite "Buff-weathering, tan to green, fine-grained massive to thinly bedded quartzite intercalated with green phyllite and schist" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Harlow Bridge quartzite member Metasedimentary Lower Ordovician to Cambrian? Omhfs Omhfs 37 41 41 0 407 bedrock schist granofels "Light-gray to grayish-green chlorite-muscovite-biotite-plagioclase-quartz schist, conspicuous sprays of hornblende, and biotite-hornblende-plagioclase granofels" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Hornblende fascicule schist and granofels member Metasedimentary / Metavolcanic Lower Ordovician to Cambrian? Omi Omi 25 27 15 0 99 bedrock limestone "Buff-streaked, dark-bluish-gray, thinly bedded and well-foliated dolomitic limestone, shown above the Champlain thrust south of Middlebury" Vermont Valley Sequence and Middlebury Synclinorium ? Middlebury Limestone Sedimentary Middle Ordovician Oml Oml 12 37 10 0 149 bedrock calcareous slate Medium-gray to black calcareous slate Cover rocks of the Saint Albans area Morses Line Slate Sedimentary Ordovician simplified description Omm Omm 34 59 23 0 324 bedrock argillite mudstone "Light-gray, powdery-weathering, and red, green and dark-gray, thinly bedded siliceous argillite and mudstone distinguished from the Indian River Slate by abundance of cherty siliceous layers" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Mount Merino Formation Metasedimentary Upper Ordovician Omp Omp 14 12 18 0 400 bedrock granofels quartzite "Light-gray to pale-green, whitish-gray-weathering, chlorite-biotite-plagioclase-quartz granofels and tectonically pinstriped granofels and feldspathic biotite quartzite" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Pinstriped granofels member Metasedimentary Lower Ordovician to Cambrian? Omq Omq 32 51 41 0 397 bedrock quartzite phyllite Light-gray laminated quartzite and vitreous quartzite interbedded with gray phyllite and schist Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Interbedded quartzite and phyllite member Metasedimentary Lower Ordovician to Cambrian? Omr Omr 63 13 70 0 409.7 bedrock metarondingite gneiss "Bright-green and white, fine- to medium-grained, variably foliated calcite-quartz-albite-mariposite-actinolite-tremolite-epidote-zoisite granofels to gneiss. Associated with greenstone and ultramafic rocks in Roxbury" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Mariposite-bearing metarondingite member Metaplutonic Lower Ordovician to Cambrian? simplified description Omw Omw 21 50 27 0 394 bedrock quartzite phyllite "Light-gray to tan, fine-grained albite-chlorite-sericite-quartz phyllitic quartzite interlayered with light-greenish-gray quartzo-feldspathic granofels and dark-gray phyllite. Contains dark-green metamorphosed mafic dikes and sills" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Truland Brook member Metasedimentary Lower Ordovician to Cambrian? Omwh Omwh 21 76 27 0 412 bedrock phyllite quartzite "Predominantly medium-dark-gray to lustrous-tan, fine-grained garnet-biotite-muscovite phyllite and carbonaceous phyllite, contains layers of dark-gray quartzite, coticule, and ironstone locally mapped separately" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Whetstone Hill Member - Phyllite facies Metasedimentary Lower Ordovician to Cambrian? Omwhb Omwhb 20 100 20 0 413 bedrock schist granofels "Dark-gray, sooty- and rusty-weathering, sulfidic biotite-muscovite-plagioclase-quartz schist and granofels, is a lateral variant of Omwh. Contains layers of rusty-weathering amphibolite, and dark-gray quartzite" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Whetstone Hill Member - Black sulfidic carbonaceous schist facies Metasedimentary Lower Ordovician to Cambrian? Omwhg Omwhg 13 90 20 0 416 bedrock metasiltstone phyllite "Pale-greenish-gray, finely laminated, magnetite-chlorite-biotite feldspathic metasiltstone and pale-greenish-yellow-weathering muscovite-chlorite-quartz phyllite" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Whetstone Hill Member - Metasiltstone facies Metasedimentary Lower Ordovician to Cambrian? Omwhq Omwhq 0 100 20 0 414 bedrock coticule quartzite "Dark-gray to light-gray, vitreous magnetite quartzite, and coticule" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Whetstone Hill Member - Coticule and quartzite facies Metasedimentary / Metavolcanic Lower Ordovician to Cambrian? Omwhv Omwhv 8 100 8 0 415 bedrock metadacite "Pale-tannish-gray- to purplish-gray-weathering, phyllitic metadacitic volcanic breccia, agglomerate, and grayish-green fragmental meta-andesitic breccia, may occur at several levels" Early to Late Taconic Accreted Terrane "Eastern allochthonous sequence, oceanic and accretionary realm" Moretown Formation Whetstone Hill Member - Metavolcanic facies Metavolcanic Lower Ordovician to Cambrian? simplified description Onb Onb 0 50 50 0 374 bedrock metatrondhjemite hornblendite "Predominantly light-gray to whitish-weathering, massive to gneissic hornblende-biotite tonalite and biotite-muscovite-quartz-plagioclase trondhjemite, includes rare hornblendite, metadiabase, and metapyroxenite" Early to Late Taconic Accreted Terrane North River Igneous Suite "Eastern allochthonous sequence, oceanic and accretionary realm" Barnard Gneiss Metaplutonic Ordovician to Late Cambrian simplified description Onbm Onbm 13 65 75 0 376 bedrock metatrondhjemite amphibolite "Heterogeneous composite intrusive well-layered unit consisting of biotite and hornblende metatrondhjemite, garnet-hornblende-plagioclase amphibolite, and metadiabase dikes" Early to Late Taconic Accreted Terrane North River Igneous Suite "Eastern allochthonous sequence, oceanic and accretionary realm" Mixed felsic and mafic rocks Metavolcanic / Metaplutonic Ordovician to Late Cambrian simplified description Onbs Onbs 55 18 55 0 372 bedrock amphibolite metatrondhjemite "Light- to dark-gray and steel-blue to apple-green, fine-grained hornblende-chlorite-plagioclase amphibolite, locally containing significant calcite and pyrite and interlayered felsic layers of metatrondhjemite or metadacite" Early to Late Taconic Accreted Terrane North River Igneous Suite "Eastern allochthonous sequence, oceanic and accretionary realm" Branch Brook Dike and Sill Complex South Pond facies Metaplutonic Ordovician to Late Cambrian simplified description Onbw Onbw 71 27 61 0 370 bedrock amphibolite "Light-green to medium-green, massive, epidote-ilmenite-sphene-chlorite-hornblende-plagioclase amphibolite, marked by coarse hornblende and abundant phenocrysts of plagioclase" Early to Late Taconic Accreted Terrane North River Igneous Suite "Eastern allochthonous sequence, oceanic and accretionary realm" Branch Brook Dike and Sill Complex Whitneyville facies Metaplutonic Ordovician to Late Cambrian simplified description Onbwm Onbwm 65 18 55 0 371 bedrock amphibolite "Dark-gray to black, poorly layered, porphyritic and nonporphyritic ilmenite-epidote-chlorite-plagioclase-hornblende amphibolite" Early to Late Taconic Accreted Terrane North River Igneous Suite "Eastern allochthonous sequence, oceanic and accretionary realm" Branch Brook Dike and Sill Complex Williamsville facies Metaplutonic Ordovician to Late Cambrian simplified description Onnt Onnt 0 40 40 0 378 bedrock metatrondhjemite metatonalite "Light-gray to cream-weathering, massive to gneissic, hornblende-biotite and muscovite-biotite metatrondhjemite and metatonalite, forms a thick sill-like intrusive" Early to Late Taconic Accreted Terrane North River Igneous Suite "Eastern allochthonous sequence, oceanic and accretionary realm" Newfane tonalite Metaplutonic Ordovician to Late Cambrian simplified description Onr Onr 13 65 75 0 377 bedrock metatrondhjemite amphibolite "Heterogeneous composite intrusive well-layered unit consisting of biotite and hornblende metatrondhjemite, garnet-hornblende-plagioclase amphibolite, and metadiabase dikes" Early to Late Taconic Accreted Terrane North River Igneous Suite "Eastern allochthonous sequence, oceanic and accretionary realm" Ruger Hill facies Metavolcanic / Metaplutonic Ordovician to Late Cambrian simplified description Ont Ont 0 70 70 0 375 bedrock metatonalite amphibolite "Medium-grayish-green, medium-grained hornblende-biotite tonalite gneiss, with minor amphibolite" Early to Late Taconic Accreted Terrane North River Igneous Suite "Eastern allochthonous sequence, oceanic and accretionary realm" Tonalite gneiss Metaplutonic Ordovician to Late Cambrian simplified description Ontd Ontd 0 40 40 0 377.5 bedrock metatrondhjemite metatonalite "Light-gray to whitish-gray, coarse-grained muscovite-biotite-quartz-plagioclase metatrondhjemite on the east flank of the Chester dome, similar to Onb, Onnt and Ontw" Early to Late Taconic Accreted Terrane North River Igneous Suite "Eastern allochthonous sequence, oceanic and accretionary realm" Metatrondhjemite and metatonalite Metaplutonic Ordovician to Late Cambrian simplified description Ontw Ontw 0 40 40 0 369.5 bedrock metatonalite metatrondhjemite "Cream-colored, light-gray- to whitish-gray-weathering, coarse-grained chlorite-biotite-muscovite-quartz-plagioclase (+/-garnet+/-hornblende) metatrondhjemite and metatonalite" Early to Late Taconic Accreted Terrane North River Igneous Suite "Eastern allochthonous sequence, oceanic and accretionary realm" West Halifax Trondhjemite Metaplutonic Ordovician to Late Cambrian Oo Oo 8 17 10 0 56 bedrock limestone "Dove-gray-weathering, black to dark-gray fine-grained limestone. Distinguished from the Middlebury Limestone with difficulty, especially in the area west of the Sudbury slice" Adirondack lowlands and Lake Champlain lowlands Black River Group Orwell Limestone Sedimentary Upper Ordovician Oobg Oobg 13 50 8 0 468.2 bedrock granite "Pink, medium-grained muscovite-biotite-microcline-perthite granite and gneissic granite, and aplite of the Lebanon dome" Bronson Hill anticlinorium or arch Oliverian Plutonic Suite Bronson Hill arch intrusive rocks Biotite granite Metaplutonic Late Ordovician Oogt Oogt 8 40 20 0 468.3 bedrock granodiorite quartz diorite "Granodioritic to quartz dioritic gneissic border phase of Oobg, perhaps in part metasomatic" Bronson Hill anticlinorium or arch Oliverian Plutonic Suite Bronson Hill arch intrusive rocks Biotite granite Granodioritic to quartz dioritic gneissic border phase Metaplutonic Late Ordovician Oohg Oohg 8 60 20 0 468.1 bedrock metagabbro "Dark-green, coarse-grained, well-foliated hornblende-andesine metagabbro" Bronson Hill anticlinorium or arch Oliverian Plutonic Suite Bronson Hill arch intrusive rocks Hornblende metagabbro Metaplutonic Late Ordovician Op Op 11 37 15 0 478 bedrock schist "Dark-gray to grayish-black, rusty-weathering sulfidic slate and phyllite interlayered with felsic volcanic rocks and tuffs and amphibolite" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Partridge Formation Sulfidic slate and phyllite member Metasedimentary Upper Ordovician Opa Opa 18 78 32 0 479.5 bedrock amphibolite Amphibolite Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Partridge Formation Amphibolite member Metavolcanic Upper Ordovician simplified description Opaw Opaw 26 50 28 0 323 bedrock wacke slate "Light-gray, tan weathering, mica-speckled, massive to thin-bedded quartz-plagioclase wacke interbedded with dark gray carbonaceous slate. Conatins autoclastic chips of gray slate, fragments of volcanics and clasts of gray quartz and oligoclase" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Pawlet Formation Metasedimentary Upper Ordovician simplified description Opi Opi 8 34 12 0 61.5 bedrock dolostone limestone "Light-buff-tan weathering, massive to thick-bedded, fine-grained dark-gray dolostone, has beeswax-scored surfaces, contains thin layers of fossiliferous blue-gray limestone" Adirondack lowlands and Lake Champlain lowlands Beekmantown Group Providence Island Dolostone Sedimentary Middle and Lower Ordovician simplified description Opo Opo 12 23 10 0 326 bedrock slate limestone "Dull-white and whitish-gray-weathering, and pale-green and gray, thinly bedded to laminated slate and phyllite. Has distinctive beds, 1 cm to several centimeters thick, of siliceous argillite and metasiltstone and locally abundant thin beds of micritic black limestone" The Taconic Allochthon Rocks of the Giddings Brook Sunset Lake and Bird Mountain slices Poultney Formation Metasedimentary Middle and Lower Ordovician Opr Opr 19 79 33 0 479 bedrock metarhyolite "Greenish-gray, light-bluish-gray, or medium-bluish-gray metarhyolite tuff, lapilli tuff, tuff breccia, and lava. Generally porphyritic with 5 to 20 percent plagioclase and, in some places, quartz phenocrysts and minor amphibolite" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Partridge Formation Metarhyolite member Metavolcanic Upper Ordovician Os Os 25 18 9 0 110 bedrock marble dolostone Predominantly light-gray- to white- and bluish-gray-streaked calcite marble and massive white- and green-streaked calcite marble. Locally contains intermediate dolostone beds Vermont Valley Sequence and Middlebury Synclinorium Shelburne Marble Sedimentary Lower Ordovician Osp Osp 0 20 0 0 52 bedrock calcareous shale limestone Dark-gray calcareous shale with beds of bluish-gray limestone Adirondack lowlands and Lake Champlain lowlands Trenton Group Stony Point Formation Sedimentary Upper Ordovician Otl Otl 6 21 9 0 97 bedrock limestone shale "Chazy, Black River, and Trenton Limestones undifferentiated - Shown locally west of the Taconic allochthon" Vermont Valley Sequence and Middlebury Synclinorium "Chazy, Black River, and Trenton Limestones undifferentiated" "Chazy, Black River, and Trenton Limestones undifferentiated" Sedimentary Upper and Middle Ordovician Ov Ov 8 44 16 0 58 bedrock limestone "Dark- to light-gray, fossiliferous limestone" Adirondack lowlands and Lake Champlain lowlands Chazy Group Valcour Formation Sedimentary Upper Ordovician Ow Ow 0 13 0 0 93 bedrock shale and phyllite limestone "Same description as Hortonville - Dark-gray siliceous shale and phyllite, contains thin beds of blue gray argillaceous limestone, minor beds of gray to tan quartzite grades into limey shales" Vermont Valley Sequence and Middlebury Synclinorium Walloomsac Formation Sedimentary Upper Ordovician simplified description Owb Owb 7 52 23 0 164 bedrock phyllite dolostone "Black to dark-gray, sulfidic to nonsulfidic, carbonaceous, fine-grained, biotite-muscovite-quartz phyllite with pods and beds of mottled dolostone, ankeritic quartzite, and rhythmically layered gray quartzite, limestone breccia and laminated silicic phyllite" "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" West Bridgewater Formation Black to dark-gray phyllite member Metasedimentary Middle Ordovician Owbg Owbg 19 52 7 0 165 bedrock phyllite dolostone "Interbedded dark-gray and grayish green, chlorite-muscovite-quartz-knotted albitic phyllite containing pods of bluish-gray dolostone. (Correlation with West Bridgewater uncertain.) Mapped only in the area west of Granville" "Ordovician, Cambrian, and Neoproterozoic cover rocks north of the Lincoln Mountain massif" West Bridgewater Formation Dark-gray and green phyllite member Metasedimentary Middle Ordovician Owbl Owbl 14 74 14 0 95 bedrock phyllite Black carbonaceous highly graptoliferous phyllite Vermont Valley Sequence and Middlebury Synclinorium Walloomsac Formation Sedimentary Upper Ordovician Owbl Owbl 13 50 0 0 322 bedrock slate "Black slate of Climacograptus bicornis Biozone on and west of Whipstock Hill, otherwise typical of slates of the Walloomsac Formation shown as Ow" The Taconic Allochthon The Taconic Allochthon Walloomsac Formation Graptoliferous slate Metasedimentary Upper Ordovician Owc Owc 12 49 21 0 487 bedrock metasiltstone quartzite "Metamorphosed gray siltstone, quartzite, volcanogenic chert, and ironstone, all typically containing coticule and magnetite" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Washburn Brook Formation Metamorphosed gray siltstone Metasedimentary / Metavolcanic Upper and Middle Ordovician Owl Owl 0 50 0 0 94 bedrock limestone Basal limestone member Vermont Valley Sequence and Middlebury Synclinorium Walloomsac Formation Sedimentary Upper Ordovician Owm Owm 0 60 13 0 91 bedrock limestone Basal limestone member - same as Oil Vermont Valley Sequence and Middlebury Synclinorium Ira Formation Whipple Marble member Sedimentary Upper Ordovician simplified description Ows Ows 6 35 18 0 486.4 bedrock breccia metasiltstone "Metamorphosed sedimentary breccia interlayered with dark-gray slate and micaceous siltstone. Clasts include Albee Formation, gray slate, coticule-bearing metasiltstone and chert, and quartz pebbles. Matrix consists of metasandstone, metasiltstone, or slate" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Washburn Brook Formation Metamorphosed sedimentary breccia Metasedimentary / Metavolcanic Upper and Middle Ordovician Oww Oww 0 60 20 0 320 bedrock breccia "Tectonic breccia formed in situ, contains abundant pseudo-pebbles" The Taconic Allochthon The Taconic Allochthon Walloomsac Formation Whipstock Breccia Metasedimentary Upper Ordovician Owwu Owwu 30 51 28 0 321 bedrock phyllite granofels Gray and grayish-green rocks associated with Whipstock breccia on Whipstock Hill but of uncertain correlation The Taconic Allochthon The Taconic Allochthon Walloomsac Formation "Sandy phyllite, granofels and cherty phyllite" Metasedimentary Upper Ordovician simplified description Sbd Sbd 70 70 13 0 456 bedrock diorite quartz diorite "Medium-gray-weathering, porphyritic dikes and sills of fine- to medium-grained hornblende-biotite diorite and quartz diorite, and coarse-grained quartz monzodiorite" Lake Memphremagog Intrusive Suite Braintree Intrusive Complex Metadiorite to metamonzodiorite Metaplutonic Late Silurian simplified description Sbg Sbg 13 20 0 0 455 bedrock granodiorite granite "Yellowish-gray to light-gray, medium- to coarse-grained magnetite-biotite-mesoperthite granodiorite and granite. Has mutually intrusive contacts with associated metadiorites" Lake Memphremagog Intrusive Suite Braintree Intrusive Complex Mount Nevis pluton "Biotite-bearing metagranodiorite, metagranite, and meta-aplite of the Mount Nevis pluton" Metaplutonic Late Silurian simplified description Sc Sc 41 91 9 0 477 bedrock quartzite "Quartzite and quartz-cobble metaconglomerate, quartz-cobble conglomerate with abundant dark-gray phyllite matrix that resembles phyllite of the Littleton Formation" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Clough Quartzite Metasedimentary Lower Silurian Scc Scc 31 61 21 0 477.5 bedrock conglomerate granofels Lower conglomerate and granofels on Skitchewaug Mountain Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Clough Quartzite Metasedimentary Lower Silurian Scg Scg 50 50 0 0 459 bedrock tonalite gabbro Nonfoliated to foliated pegmatitic metatonalite to metagabbro Lake Memphremagog Intrusive Suite Comerford Intrusive Complex Pegmatitic metatonalite to metagabbro Metaplutonic Late Silurian simplified description Scm Scm 40 50 0 0 458 bedrock gabbro dioriite "Foliated to non-foliated, fine-grained to pegmatitic metagabbro, metadiorite, and metatonalite, aplitic metatonalite, and metadiabase" Lake Memphremagog Intrusive Suite Comerford Intrusive Complex "Pegmatitic metagabbro, metadiorite, and metatonalite" Metaplutonic Late Silurian Scq Scq 25 81 13 0 477.6 bedrock quartzite Upper quartzite on Skitchewaug Mountain Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Clough Quartzite Metasedimentary Lower Silurian simplified description Scv Scv 39 57 17 0 452 bedrock quartzite amphibolite "Heterogeneous, thin (<10 m-thick) unit of interbedded quartzite, amphibolite, felsic granofels and phyllite occurring at the base of the Waits River Formation on the north end of the Chester dome" Connecticut Valley Trough Connecticut Valley Trough Shaw Mountain Formation Basal volcaniclastic and metasedimentary member Metasedimentary Upper to Lower Silurian Sf Sf 40 70 13 0 474 bedrock metalimestone metasandstone "Metamorphosed limestone, calcareous sandstone, siltstone, and pelite. Some limestone conglomerate and polymict conglomerate with calcareous matrix" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Fitch Formation Metasedimentary Lower Devonian and Upper Silurian Sg Sg 30 60 8 0 461 bedrock schist granofels "Thin-bedded muscovite-biotite-garnet-staurolite-kyanite schist and micaceous quartz-feldspar granofels, some calc-silicate lenses and layers" Piermont and other allochthons Piermont and other allochthons Greenvale Cove Formation Metasedimentary Lower Silurian simplified description Sn Sn 13 30 0 0 448 bedrock phyllite quartzite "Dark-gray to silvery-gray, lustrous, fine-grained carbonaceous quartz-muscovite phyllite and silicic phyllite, and garnet-rich biotite-muscovite-quartz schist, contains beds of gray quartzite and metasiltstone, beds of quartz-feldspar grit or quartzite near base, and minor quartzose limestone" Connecticut Valley Trough Connecticut Valley Trough Northfield Formation carbonaceous phyllite member Metasedimentary Upper Silurian simplified description Snd Snd 30 40 0 0 454 bedrock diorite trondhjemite "Metamorphosed diorite, trondhjemite, and diabase, consisting of massive to foliated, light-gray to grayish-green, chalky-weathering diorite with xenoliths of green phyllite and trondhjemite, and massive, tan-weathering, medium- to coarse-grained trondhjemite with xenoliths of diabase" Lake Memphremagog Intrusive Suite Newport Intrusive Complex Diorite and trondhjemite Metaplutonic Late Silurian Sng Sng 8 13 0 0 453 bedrock granodiorite "Tan to light-bluish-gray, brown-weathering, medium- to coarse-grained, equigranular to porphyritic foliated granodiorite composed of quartz, plagioclase, perthite, microcline, biotite, and sericite" Lake Memphremagog Intrusive Suite Newport Intrusive Complex Granodiorite Metaplutonic Late Silurian simplified description Snl Snl 20 50 8 0 449 bedrock phyllite metalimestone "Dark-gray to silvery-gray, carbonaceous quartz-muscovite silicic slate phyllite or schist with as much as 5 percent beds of punky limestone west of the Guilford dome" Connecticut Valley Trough Connecticut Valley Trough Northfield Formation carbonaceous phyllite and limestone member Metasedimentary Upper Silurian Snq Snq 24 48 9 0 450 bedrock metawacke quartzite "Dark-gray, quartz-pebble metawacke and gray quartzite and conglomerate at base of the Northfield Formation, south of Springfield" Connecticut Valley Trough Connecticut Valley Trough Northfield Formation "Quartzite, grit and conglomerate member" Metasedimentary Upper Silurian simplified description Sr Sr 20 40 0 0 460 bedrock granofels schist "Interlayered, commonly rusty-weathering quartz-feldspar micaceous granofels and dark-gray mica schist containing porphyroblasts of garnet, staurolite, and kyanite. Calc-silicate lenses common in the granofels, granule and pebble metaconglomerate" Piermont and other allochthons Piermont and other allochthons Rangeley Formation Schist member Metasedimentary Lower Silurian simplified description Src Src 41 72 15 0 460.6 bedrock conglomerate Quartz conglomerate Piermont and other allochthons Piermont and other allochthons Rangeley Formation Conglomerate member Metasedimentary Lower Silurian simplified description Srr Srr 40 56 20 0 460.3 bedrock schist Rusty sulfidic schist Piermont and other allochthons Piermont and other allochthons Rangeley Formation Sulfidic schist member Metasedimentary Lower Silurian simplified description Ss Ss 67 85 18 0 451 bedrock conglomerate quartzite "White to yellowish-gray, quartz-pebble conglomerate to conglomeratic quartzite with quartzite matrix and phyllitic quartzite, quartz-pebble to -granule phyllite and vitreous quartzite in beds as much as 5 m thick" Connecticut Valley Trough Connecticut Valley Trough Shaw Mountain Formation conglomerate member Metasedimentary / Metavolcanic Upper to Lower Silurian simplified description Ssm Ssm 55 72 12 0 475 bedrock phyllite metasandstone "Greenish-gray to dark-gray, pyritic, locally calcareous phyllite and light-gray, locally pyritic and calcareous, fine- to medium-grained, feldspar-rich metasandstone, some beds are punky weathering. Graded grit and conglomerate beds toward base" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Sawyer Mountain Formation Metasedimentary Devonian and Silurian Svf Svf 43 49 25 0 476 bedrock metafelsite "Felsic metavolcanic rocks includes volcanic debris flow, laminated tuff, and strongly foliated felsite" Bronson Hill anticlinorium or arch Stratified rocks of the Bronson Hill arch and Sawyer Mountain belt Metavolcanic Silurian simplified description Tmb Tmb 30 6 50 0 1 bedrock lignite sand silt gravel "Organic, silt, sand, gravel and slumped and dismembered lignite occurring as elongate disrupted deposits in underlying kaolin, residual hematite and ochre deposits near Brandon" Brandon Lignite Brandon Lignite Sedimentary Lower Miocene simplified description Y?cms Y?cms 49 19 20 0 249 bedrock schist "Light-silvery-green to grayish-green, lustrous muscovite-chlorite-quartz (+/-garnet+/-chloritoid+/-ilmenite) schist and biotite-albite-muscovite-quartz schist" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Problematic rocks at Devils Den in Weston and Danby areas (Mesoproterozoic?) Muscovite-chlorite-garnet schist Metasedimentary Mesoproterozoic? simplified description Y?dm Y?dm 66 13 12 0 251 bedrock marble schist "Beige to pinkish-gray-weathering, pyrite-bearing, medium- and fine-grained phlogopite-chlorite-dolomite marble exposed in cliffs east of the road at Devils Den" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Problematic rocks at Devils Den in Weston and Danby areas (Mesoproterozoic?) Dolomite marble Metasedimentary Mesoproterozoic? simplified description Y?mfs Y?mfs 44 27 27 0 250 bedrock schist "A highly heterogeneous unit, distinguished from Y?cms by its generally rusty-weathering, nonlustrous appearance and by the abundance of large albite crystals, conspicuous large plates of muscovite and biotite, and abundant clinozoisite" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Problematic rocks at Devils Den in Weston and Danby areas (Mesoproterozoic?) Biotite-muscovite-plagioclase-quartz schist Metasedimentary Mesoproterozoic? simplified description Y?q Y?q 20 100 50 0 251.5 bedrock quartzite "Light-gray to pinkish-gray, magnetite-muscovite-plagioclase quartzite at Devils Den" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Problematic rocks at Devils Den in Weston and Danby areas (Mesoproterozoic?) Quartzite Metasedimentary Mesoproterozoic? "Y1,2be" "Y1,2be" 44 55 41 0 277 bedrock gneiss quartzite "Light-pale-yellowish-green to gray quartzite gneiss containing abundant epidote and locally magnetite, and frosted round grains of quartz associated with diopside-bearing quartzite" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Biotite-epidote-quartz gneiss and epidotic quartzite Metasedimentary / Metavolcanic Middle and Early Mesoproterozoic simplified description "Y1,2bg" "Y1,2bg" 16 11 11 0 276 bedrock gneiss "A widespread heterogeneous unit of well-layered, predominantly biotite-quartz-plagioclase gneisses containing variable amounts of magnetite, hornblende, and garnet, and little potash feldspar" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Biotite-quartz-plagioclase gneiss Metasedimentary / Metavolcanic Middle and Early Mesoproterozoic simplified description Y1?cm Y1?cm 71 22 10 0 255 bedrock marble calc-silicate gneiss "Includes white, coarse-grained calcite marble, beige to gray, medium- to coarse-grained phlogopite-tremolite-dolomite-quartz-(+/-talc) marble, greenish actinolite-dolomite-calcite marble, phlogopite-diopside-scapolite-calcite-dolomite marble" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Cavendish Formation Marble and calc-silicate member Metasedimentary Early Mesoproterozoic simplified description Y1a Y1a 75 27 75 0 273 bedrock amphibolite "Dark-grayish-green, fine-grained quartz-hornblende-plagioclase amphibolite, locally garnetiferous and medium-grained hornblende-plagioclase amphibolite" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Amphibolite Metasedimentary / Metavolcanic Early Mesoproterozoic simplified description Y1bm Y1bm 31 8 60 0 245 bedrock tonalite gneiss amphibolite "Light-gray to whitish-gray-weathering, medium-grained biotite-quartz-plagioclase gneiss flecked with coarse biotite. Contains numerous lenses of fine-grained amphibolite" Laurentian basement South Londonderry Igneous Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Baileys Mills tonalitic gneiss Tonalite gneiss Metaplutonic Early Mesoproterozoic Y1bmp Y1bmp 31 8 60 0 246 bedrock tonalite gneiss amphibolite Coarse-grained facies of the Baileys Mills tonalitic gneiss exposed on the northeast flank of the Chester dome Laurentian basement South Londonderry Igneous Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Baileys Mills tonalitic gneiss Plagioclase-phenocrystic tonalite gneiss Metaplutonic Early Mesoproterozoic simplified description Y1cfs Y1cfs 54 34 54 0 254 bedrock granofels gneiss "Light-gray to medium-dark-gray, rusty-weathering, white-plagioclase-spotted biotite-quartz-plagioclase granofels, massive grayish-green chlorite-spotted, magnetite-studded, biotite-plagioclase-quartz granofels and gneiss, and porphyroclastic plagioclase-augen-biotite mylonite gneiss" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Cavendish Formation Feldspathic schist and granofels member Metasedimentary / Metaplutonic Early Mesoproterozoic simplified description Y1cg Y1cg 17 10 45 0 253 bedrock schist granofels "Lustrous, yellowish-grayish-green, ilmenite-staurolite (+/-kyanite)-garnet (large) -plagioclase-biotite-muscovite-quartz schist and warty-textured, dark-gray, biotite-rich garnet (large)-plagioclase-quartz schist, local granofels with chlorite pseudomorphs after garnet" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Cavendish Formation Gassetts Schist Member Metasedimentary Early Mesoproterozoic simplified description Y1cs Y1cs 71 22 10 0 255.5 bedrock calc-silicate gneiss marble "Coarse-grained dark-green diopside (+/-hornblende+/-zoisite)-calc-silicate rocks, white talc-tremolite (+/-dolomite)-calc-silicate schist, and minor quartzite, diopside quartzite, and schistose bluish-gray marble" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Cavendish Formation Marble and calc-silicate member Metasedimentary Early Mesoproterozoic simplified description Y1dg Y1dg 42 18 59 0 244 bedrock diorite gneiss gabbro gneiss "Coarse-grained hornblende-plagioclase (+/-quartz) dioritic gneiss and gabbroic gneiss mapped in the Londonderry area, where it is interpreted as metagabbro" Laurentian basement South Londonderry Igneous Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Hornblende diorite gneiss Metaplutonic Early Mesoproterozoic simplified description Y1fg Y1fg 31 8 60 0 248 bedrock trondhjemite gneiss granodiorite gneiss "Light-gray to whitish-gray-weathering, magnetite-biotite-microcline-quartz-plagioclase metatrondhjemite to granodioritic gneiss. Intrudes paragneiss units of the Chester dome" Laurentian basement South Londonderry Igneous Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Felchville Gneiss Felchville trondhjemite facies Metaplutonic Early Mesoproterozoic simplified description Y1fga Y1fga 22 10 85 0 247 bedrock aplite gneiss trondhjemite gneiss "Light-gray to whitish-gray, fine-grained, magnetite trondhjemitic gneiss and aplitic trondhjemite, intricately intrusive into layered paragneisses of the Chester dome. Contains xenoliths of more mafic gneiss" Laurentian basement South Londonderry Igneous Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Felchville Gneiss Felchville aplitic facies Metaplutonic Early Mesoproterozoic simplified description Y1q Y1q 72 72 10 0 269 bedrock quartzite schist "Tan to rusty brown or gray thinly layered garnet-biotite-quartzite and schistose quartzite associated with aluminous schists, calc-silicate rocks or interbedded within biotite-quartz-plagioclase paragneiss" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex "Quartzite, undifferentiated" Metasedimentary Early Mesoproterozoic Y1rs Y1rs 9 15 9 0 278 bedrock schist amphibolite Rusty-weathering sulfidic schist and minor amphibolite older than part of the South Londonderry Igneous Suite Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Quartz schist Metasedimentary Early Mesoproterozoic simplified description Y1rt Y1rt 31 8 60 0 241 bedrock trondhjemite gneiss aplite gneiss "Chalky-white to light-gray-weathering, medium- to coarse-grained biotite metatrondhjemite and aplite (Y1rta)" Laurentian basement South Londonderry Igneous Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Rawsonville trondhjemite gneiss Metaplutonic Early Mesoproterozoic simplified description Y1rta Y1rta 49 20 67 0 242 bedrock aplite gneiss Aplite in Y1rt Laurentian basement South Londonderry Igneous Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Rawsonville trondhjemite gneiss Metaplutonic Early Mesoproterozoic simplified description Y1tg Y1tg 31 8 60 0 243 bedrock tonalite gneiss "Medium-gray- to light-gray-weathering, biotite (+/-hornblende) tonalite gneiss exposed on Torment Hill in Weston" Laurentian basement South Londonderry Igneous Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Tonalite gneiss Metaplutonic Early Mesoproterozoic simplified description Y2a Y2a 75 19 55 0 274 bedrock amphibolite "Dark-grayish-green, fine-grained quartz-hornblende-plagioclase amphibolite, locally garnetiferous and medium-grained hornblende-plagioclase amphibolite" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Amphibolite Metasedimentary / Metavolcanic Middle Mesoproterozoic Y2ap Y2ap 75 55 100 0 230 bedrock granite gneiss "Light-gray to white, fine-grained aplitic granite gneiss as border of Y2gg or thin dikes or sills in paragneiss units" Laurentian basement Stratton Mountain Intrusive Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Aplitic gneiss Metaplutonic Middle Mesoproterozoic simplified description Y2ba Y2ba 55 45 58 0 79 bedrock mafic gneiss Mafic gneiss "Rocks of the Adirondacks in Vermont and in the Whitehall, NY area" Mafic gneiss Metaplutonic Middle Mesoproterozoic simplified description Y2bgt Y2bgt 25 18 5 0 260 bedrock gneiss quartzite "Steel-gray-weathering, garnet (small)-quartz-biotite gneiss and quartzite" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Aluminous schist and gneiss Quartz schist and gneiss Metasedimentary Middle Mesoproterozoic simplified description Y2bmg Y2bmg 21 7 19 0 85 bedrock mafic gneiss quartzite "Dark-gray to black, fine-grained, magnetite-garnet-hornblende-biotite-diopside-plagioclase gneiss, commonly containing beds of quartzite, tremolite-pyroxene gneiss, schist, and sulfidic quartzite" "Rocks of the Adirondacks in Vermont and in the Whitehall, NY area" Mafic gneiss Metasedimentary / Metavolcanic Middle to Early Mesoproterozoic Y2bpg Y2bpg 29 11 38 0 84 bedrock paragneiss mafic gneiss "Light-greenish-gray to pinkish-gray well-foliated, and well-layered quartz-rich gneiss and more mafic biotite-hornblende-pyroxene-quartz-plagioclase gneiss irregularly distributed within unit" "Rocks of the Adirondacks in Vermont and in the Whitehall, NY area" Biotite-plagioclase quartz gneiss Metasedimentary / Metavolcanic Middle to Early Mesoproterozoic simplified description Y2bt Y2bt 38 26 35 0 78 bedrock tonalite gneiss mafic gneiss "Predominantly chalky-white weathering, massive biotite tonalite gneiss having screens, dikes, or sills of more mafic gneiss. Passes laterally into white, fine-grained trondhjemitic aplite near contacts with larger screens of paragneiss" "Rocks of the Adirondacks in Vermont and in the Whitehall, NY area" Biotite tonalite gneiss Metaplutonic Middle Mesoproterozoic simplified description Y2bv Y2bv 30 0 60 0 240 bedrock trondhjemite gneiss "Light-gray to whitish-gray, fine-grained biotite trondhjemitic gneiss, locally containing abundant magnetite" Laurentian basement South Londonderry Igneous Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Bondville metadacite and trondhjemite gneiss Metaplutonic Middle Mesoproterozoic simplified description Y2ch Y2ch 55 45 100 0 231 bedrock granodiorite gneiss pegmatite "Light-gray to medium-dark-gray, porphyritic biotite-microcline-perthite granodioritic gneiss and pegmatite. Strongly deformed, lineated and saturated with less deformed later pegmatite, migmatitic border exhibits fewer microcline megacrysts" Laurentian basement Stratton Mountain Intrusive Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex College Hill Granite Gneiss Metaplutonic Middle Mesoproterozoic simplified description Y2cp Y2cp 16 16 76 0 239 bedrock tonalite gneiss diorite gneiss "Gray to medium-dark-gray, biotite-rich metatonalite gneiss, having irregular screens, and xenoliths of more mafic hornblende-biotite tonalite or diorite gneiss" Laurentian basement South Londonderry Igneous Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Cole Pond tonalite gneiss Metaplutonic Middle Mesoproterozoic Y2cs Y2cs 72 33 10 0 83 bedrock marble calc-silicate gneiss "Medium-dark-gray to light-gray diopside-phlogopite-scapolite-calcite marble, phlogopite-tremolite-talc schist, and dark-gray diopside-hornblende (actinolite)-plagioclase calc-silicate gneiss" "Rocks of the Adirondacks in Vermont and in the Whitehall, NY area" Marble and calc-silicate gneiss Metasedimentary Middle Mesoproterozoic simplified description Y2dm Y2dm 65 17 12 0 270 bedrock marble schist "Light-gray to yellowish-gray, coarse-grained dolomite-phlogopite-scapolite marble, pyritiferous varieties weather salmon pink to beige. Commonly associated with tremolite-talc marble and tremolite-talc schist" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Dolomite marble Metasedimentary Middle Mesoproterozoic simplified description Y2gg Y2gg 55 45 100 0 229 bedrock granite gneiss granodiorite gneiss "A heterogeneous unit consisting of granitic and granodioritic and aplite biotitic microcline-rich gneisses, highly gneissic and locally migmatitic occurring in the southern part of the Green Mountain massif" Laurentian basement Stratton Mountain Intrusive Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Biotite-granitic gneiss Metaplutonic Middle Mesoproterozoic Y2hg Y2hg 31 22 12 0 275 bedrock diorite gneiss Medium- to coarse-grained hornblende dioritic-appearing gneiss Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Hornblende-plagioclase gneiss Metavolcanic / Metaplutonic Middle Mesoproterozoic simplified description Y2hgn Y2hgn 31 22 12 0 81 bedrock paragneiss quartzite "Yellowish-grayish-green to rusty-sulfidic-weathering, garnet-sillimanite-biotite-orthoclase-plagioclase-quartz schist or gneiss, locally containing mappable and discontinuous lenses, layers or pods of quartzite, marble, or calc-silicate rock" "Rocks of the Adirondacks in Vermont and in the Whitehall, NY area" Hague Gneiss Metasedimentary Middle Mesoproterozoic Y2lg Y2lg 55 28 65 0 231.5 bedrock granite gneiss "Heterogeneous unit consists of medium-grained biotite-microcline-plagioclase gneiss and pinkish-gray, medium- to coarse-grained and microcline-perthite granitic gneiss. Interpreted as intrusive granitic rock older than Y3 rocks of Chittenden Intrusive Suite" Laurentian basement Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Granitic gneiss of Lincoln Mountain massif Metaplutonic Middle Mesoproterozoic simplified description Y2lga Y2lga 7 10 62 0 235 bedrock aplite gneiss "Light-gray to white, very fine grained microcline-plagioclase-quartz (+/-magnetite) aplitic gneiss contains sparing amounts of biotite, and secondary muscovite. Unit interpreted as a border facies of Y2lgg" Laurentian basement South Londonderry Igneous Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Ludlow Mountain aplitic gneiss Metaplutonic Middle Mesoproterozoic simplified description Y2lgg Y2lgg 7 10 62 0 234 bedrock granodiorite gneiss aplite gneiss "Light-gray, medium- to fine-grained garnet-biotite-microcline-perthite granodiorite, magnetite-studded white aplite, and kyanite-tourmaline pegmatite. Contains 0.5-cm clots of muscovite possibly after beryl" Laurentian basement South Londonderry Igneous Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Ludlow Mountain granodiorite gneiss Metaplutonic Middle Mesoproterozoic simplified description Y2lq Y2lq 40 40 0 0 267 bedrock quartzite phyllite "Light-tan to whitish-gray, massive vitreous quartzite in beds several meters thick, interlayered with rusty-grayish-brown garnet-muscovitic quartzite and aluminous sericite-muscovite-tourmaline retrograde phyllite" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Okemo Quartzite Metasedimentary Middle Mesoproterozoic Y2m Y2m 65 17 12 0 271 bedrock marble calc-silicate gneiss "Light blue-gray and white coarse-grained and medium-grained calcite diopside marble calcite-diopside-talc marble in beds or pods less than 5 m thick, interbedded with or passes laterally into other calc-silicate rock" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Calcite marble Metasedimentary Middle Mesoproterozoic simplified description Y2mig Y2mig 31 12 12 0 232 bedrock migmatite gneiss granite gneiss "Light-gray and pinkish-gray to yellowish-gray, massive, medium-grained plagioclase granitic gneiss and migmatite-veined biotite plagioclase gneiss. A mixed rock of uncertain origin" Laurentian basement Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Migmatitic and mylonitic rocks of uncertain origin Migmatitic gneiss Metasedimentary / Metaplutonic Middle Mesoproterozoic? Y2myu Y2myu 29 10 22 0 233 bedrock mylonitic gneiss "Highly schistose, biotite-muscovite (+/-chlorite) feldspathic mylonite and mylonitic gneiss mapped near Brandon Gap and in the Pine Hill slice west of Wallingford as Yur" Laurentian basement Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Migmatitic and mylonitic rocks of uncertain origin Mylonitic gneiss Metasedimentary / Metaplutonic Middle Mesoproterozoic? Age uncertain simplified description Y2pha Y2pha 8 5 63 0 238 bedrock aplite gneiss Aplitic and hornblende-rich reaction zones where granodiorite gneiss of Y2phg is in contact with calc-silicate rocks Laurentian basement South Londonderry Igneous Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Proctor Hill granodiorite gneiss Metaplutonic Middle Mesoproterozoic simplified description Y2phg Y2phg 7 10 62 0 237 bedrock granodiorite gneiss granite gneiss "Gray to pinkishgray, gneissoid magnetite-biotite-microcline-perthite granodiorite, and locally microcline megacrystic gneissic granite, well-foliated and highly variable in composition" Laurentian basement South Londonderry Igneous Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Proctor Hill granodiorite gneiss Metaplutonic Middle Mesoproterozoic simplified description Y2q Y2q 72 72 10 0 268 bedrock quartzite schist "Tan to rusty brown or gray thinly layered garnet-biotite-quartzite and schistose quartzite associated with aluminous schists, calc-silicate rocks or interbedded within biotite-quartz-plagioclase paragneiss" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex "Quartzite, undifferentiated" Metasedimentary Middle to Early Mesoproterozoic simplified description Y2qz Y2qz 72 72 10 0 82 bedrock quartzite "Light-tan to yellowish-gray, massive to well-layered magnetite-garnet quartzite and magnetite-biotite-garnet quartzite in beds as much as 10 m thick" "Rocks of the Adirondacks in Vermont and in the Whitehall, NY area" Quartzite Metasedimentary Middle Mesoproterozoic Y2rgt Y2rgt 9 15 9 0 275.5 bedrock gneiss "Dark-gray- to rusty-grayish-brown-weathering, sulfidic muscovite-biotite-magnetite gneiss or schist marked by abundant small garnets, biotite, and fine laminae of quartz and plagioclase. Contains thin belts of amphibolite and calc-silicate gneiss" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Garnet-biotite gneiss Metasedimentary Middle Mesoproterozoic simplified description Y2rs Y2rs garnet overprint 24 32 12 0 259 bedrock gneiss schist "Tan garnet-muscovite-biotite-quartz-plagioclase gneiss and rusty schist, locally containing abundant chloritized garnet, lustrous yellowish-grayish-green phyllonitic retrograde varieties contain chloritoid-chlorite and relict garnet (red dot overprint)" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Aluminous schist and gneiss Quartz schist and gneiss Metasedimentary Middle Mesoproterozoic Y2rss Y2rss 24 32 12 0 261 bedrock schist quartzite "Dark-gray, rusty-weathering carbonaceous to graphitic schist associated with quartzite and calc-silicate rock near Killington" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Carbonaceous sulfidic schist Metasedimentary Middle Mesoproterozoic simplified description Y2wg Y2wg 23 21 17 0 258 bedrock schist quartzite "Dark-rusty-grayish-brown-weathering, graphitic garnet-plagioclase-biotite-quartz (+/-sillimanite) schist, rusty-weathering blue-quartz-ribbed quartz schist, garnet quartzite and rusty-weathering layers of sulfidic calc-silicate rock" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Aluminous schist and gneiss Washington Gneiss Metasedimentary Middle Mesoproterozoic simplified description Y2wxcs Y2wxcs 85 39 23 0 265 bedrock calc-silicate gneiss marble "Dark-green, massive, diopside-hornblende rock, lenses of bluish-gray to gray, medium- to coarse-grained calcite marble and calcite-diopside marble and dolomitic talc-phlogopite-tremolite schist" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Wilcox Formation Calc-silicate gneiss and marble member Metasedimentary Middle Mesoproterozoic simplified description Y2wxd Y2wxd 65 29 15 0 266 bedrock marble "Beige-weathering to whitish-gray, fine-grained dolomite marble" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Wilcox Formation Dolomite marble member Metasedimentary Middle Mesoproterozoic simplified description Y2wxg Y2wxg 26 29 33 0 264 bedrock quartzite schist "Lustrous muscovite-chlorite-chloritoid or muscovite-chlorite-biotite-clinozoisite retrograde schistose quartzite and large-garnet schist. Resembles a retrograde variety of the Hague Gneiss (of Alling, 1918) (Y2hgn) near Whitehall, NY" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Wilcox Formation Garnetiferous quartzite and quartz schist member Metasedimentary Middle Mesoproterozoic simplified description Y2wxq Y2wxq 65 74 20 0 263 bedrock quartzite gneiss "Tan, yellow-gray weathering garnet-muscovite-quartzite and feldspathic retrograde garnet quartz gneiss" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Wilcox Formation Quartzite member Metasedimentary Middle Mesoproterozoic simplified description Y2wxs Y2wxs 9 15 9 0 262 bedrock schist quartzite Lustrous to rusty weathering biotite-muscovite+/-chloritoid and retrograde coarse-garnet schist Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Wilcox Formation Wilcox Formation Metasedimentary / Metaplutonic Middle Mesoproterozoic simplified description Y3Abga Y3Abga 23 16 23 0 256 bedrock gneiss "Gray or greenish-gray, albite- and magnetite-studded granulose biotite-quartz-plagioclase gneiss, containing chloritized biotite and garnet. Occurs as altered varieties of Y1,2bg near Y3Ama" Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Altered rocks adjacent to the Chittenden Intrusive Suite Albite-magnetite studded gneiss Metasedimentary / Metaplutonic Late Mesoproterozoic simplified description Y3Afg Y3Afg 20 24 18 0 219 bedrock albitic gneiss pegmatite "Massive, lineated, light-tannish-gray to gray-green, medium-grained, granulose, epidote-magnetite-biotite (chlorite)-muscovite-albite-quartz gneiss, veined with magnetite, spots of ankerite, clots of chlorite after original amphibole, pyroxene or garnet" Laurentian basement Intrusive rocks Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Granulose albitic gneiss Metaplutonic Mesoproterozoic? simplified description Y3Ag Y3Ag 0 70 100 0 222 bedrock granite gneiss More equigranular granitic gneiss than Y3Ama with which it passes locally into Laurentian basement Chittenden Intrusive Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Microcline-augen granite and monzogranite gneiss Metaplutonic Mesoproterozoic Y3Agb Y3Agb 25 9 25 0 75 bedrock metagabbro diorite Garnet-hornblende (+/-olivine) gabbro and dioritic gneiss and biotite-hornblende (+/-pyroxene) gabbro and diorite Chittenden Intrusive Suite "Rocks of the Adirondacks in Vermont and in the Whitehall, NY area" Metagabbro Metaplutonic Late Mesoproterozoic Y3Agd Y3Agd 25 9 25 0 76 bedrock granodiorite gneiss quartz monzonite gneiss "Light-gray to pinkish-gray, garnet-biotite-plagioclase-microperthite augen granodioritic gneiss, locally massive but well foliated. Contains deformed phenocrysts (augen) aligned in old relict flow(?) foliation" "Rocks of the Adirondacks in Vermont and in the Whitehall, NY area" Granodioritic augen gneiss and quartz monzonite gneiss Metaplutonic Late Mesoproterozoic simplified description Y3Agg Y3Agg 0 70 100 0 226 bedrock augen gneiss granite gneiss "Light-gray, coarse-grained, biotite-microcline megacrystic to even-grained granite gneiss closely associated with 1149- Ma to 1120-Ma augen gneisses, in the northern part of the Green Mountain massif" Laurentian basement Chittenden Intrusive Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Granitic gneiss of Chittenden Intrusive Suite (?) Metaplutonic Mesoproterozoic Y3Ala Y3Ala 0 50 80 0 227 bedrock augen gneiss "Light- to medium-gray, medium-grained, biotite-quartz-plagioclase-microcline gneiss, contains microcline augen as much as 4 cm in length" Laurentian basement Chittenden Intrusive Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Microcline augen gneiss of Lincoln Mountain massif Metaplutonic Mesoproterozoic simplified description Y3Ama Y3Ama 10 75 100 0 221 bedrock granite gneiss monzogranite gneiss "Gray to whitish-gray, coarse-grained biotite-microcline megacrystic granite and monzogranitic gneiss. Enclaves of paragneiss are locally albitized and enriched in magnetite. Enclaves of altered aluminous rocks with restites of chloritoid and sericite" Laurentian basement Chittenden Intrusive Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Microcline-augen granite and monzogranite gneiss Metaplutonic Mesoproterozoic simplified description Y3Amb Y3Amb 10 75 100 0 224 bedrock augen gneiss diorite gneiss "Pinkish-gray to medium-dark-gray, biotite-magnetite-microcline-plagioclase augen gneiss. Unit is associated with minor exposures of metadiorite to tonalitic gneisses" Laurentian basement Chittenden Intrusive Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Microcline-magnetite augen gneiss at Brandon Gap Metaplutonic Mesoproterozoic Y3Ap Y3Ap 0 70 100 0 225 bedrock pegmatite granite "Pinkish-gray to light-gray, biotite (+/-muscovite+/-tourmaline+/-magnetite) pegmatite and pegmatoid granite associated with augen gneisses of Chittenden Intrusive Suite, in Brandon" Laurentian basement Chittenden Intrusive Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Granite pegmatite and pegmatoid granite Metaplutonic Mesoproterozoic simplified description Y3Apg Y3Apg 0 70 100 0 223 bedrock granite gneiss pegmatite gneiss Biotite pegmatoid granitic gneiss locally muscovite-bearing Laurentian basement Chittenden Intrusive Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Microcline-augen granite and monzogranite gneiss Metaplutonic Mesoproterozoic simplified description Y3Aphg Y3Aphg 19 8 5 0 77 bedrock charnokite gneiss granite gneiss "Rusty-grayish-brown- to brown-weathering, knubbly coarse-grained magnetite-garnet-hornblende and pyroxene-bearing charnockitic gneiss and garnet-hornblende granite gneiss" "Rocks of the Adirondacks in Vermont and in the Whitehall, NY area" Pharoah Mountain Gneiss Metaplutonic Late to Middle Mesoproterozoic Y3Bg Y3Bg 30 90 49 0 218 bedrock granite Light-gray biotite granite gneiss containing abundant rose-colored zircon confined to the Pine Hill slice Laurentian basement Intrusive rocks Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Albitic biotite granite and pegmatite at Baker Brook Metaplutonic Mesoproterozoic Y3Bp Y3Bp 30 90 49 0 217 bedrock pegmatite "Pinkish-gray garnet-biotite-albite pegmatite and granitic augen gneiss, distinguished by abundant rose-colored zircon" Laurentian basement Intrusive rocks Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Albitic biotite granite and pegmatite at Baker Brook Metaplutonic Mesoproterozoic simplified description Y3Cbsa Y3Cbsa 20 42 90 0 213 bedrock granite aplite "White to pinkish gray, medium-grained plagioclase-microcline-perthite aplitic to pegmatitic granite forms dikes in country rocks and irregular border facies" Laurentian basement Cardinal Brook Intrusive Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Somerset Reservoir Granite Metaplutonic Neoproterozoic simplified description Y3Ccbbh Y3Ccbbh 20 42 90 0 215 bedrock granite augen gneiss "Light-pinkish-gray to gray, very coarse grained to medium-grained and mylonitic biotite-plagioclase-quartz-microcline augen gneiss, locally has large ovoidal relict microcline with rapakivi rims and intrusive breccia" Laurentian basement Cardinal Brook Intrusive Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Bull Hill Gneiss Metaplutonic Neoproterozoic Y3Ccbhr Y3Ccbhr 20 42 90 0 214 bedrock granite augen gneiss "Light-gray to pinkish gray, biotite-plagioclase-microcline megacrystic granite and augen gneiss, rapakivi texture locally preserved, occurs in the Rayponda and Sadawga domes" Laurentian basement Cardinal Brook Intrusive Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Harriman Reservoir Granite Metaplutonic Neoproterozoic simplified description Y3Ccbs Y3Ccbs 20 42 90 0 210 bedrock granite ferrodiorite "Light-gray to medium-gray, very coarse grained biotite-plagioclase-microcline rapakivi granite, contains large megacrysts of microcline perthite having rims of plagioclase that contain inclusions of biotite and garnet" Laurentian basement Cardinal Brook Intrusive Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Stamford Granite Metaplutonic Neoproterozoic simplified description Y3Ccbsa Y3Ccbsa 20 42 90 0 211 bedrock granite "Fine-grained facies consisting of white-weathering, muscovite-biotite-microcline-plagioclase aplitic granite locally forms a border facies or thin internal dikes" Laurentian basement Cardinal Brook Intrusive Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Stamford Granite Metaplutonic Neoproterozoic simplified description Y3Ccbsr Y3Ccbsr 20 42 90 0 212 bedrock granite augen gneiss "Light-gray to pinkish-gray, biotite-plagioclase-microcline megacrystic granite and augen gneiss, rapakivi texture locally preserved. Unit occurs in the Rayponda and Sadawga domes" Laurentian basement Cardinal Brook Intrusive Suite Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Somerset Reservoir Granite Metaplutonic Neoproterozoic simplified description Y3Cp Y3Cp 45 100 50 0 216 bedrock pegmatite "Light-gray to pinkish-gray, biotite-muscovite (+/-garnet+/-tourmaline+/-magnetite) granite pegmatite as crosscutting pods and larger bodies. Albitic garnet-muscovite pegmatite common " Laurentian basement Intrusive rocks Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Pegmatite Pegmatite Metaplutonic Mesoproterozoic simplified description Yur Yur 25 90 35 0 257 bedrock gneiss Retrograde aluminous gness shown above Pine Hill thrust near South Wallingford. See also Y2myu Laurentian basement Paragneiss Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mount Holly Complex Aluminous schist and gneiss Retrograde gneiss Metasedimentary / Metaplutonic Mesoproterozoic Zd Zd 52 27 59 0 209 bedrock metadiabase "Medium- to coarse-grained, foliated, actinolite-chlorite-calcite-epidote retrograded metadiabasic dikes, commonly have relict diabasic texture" Laurentian basement Intrusive rocks Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes Mafic dikes Metaplutonic Neoproterozoic Zdi Zdi 52 27 59 0 73 bedrock diabase basalt "Dark-gray to greenish-gray, very fine grained, ocellar basaltic to medium-grained augite-plagioclase diabasic dikes, occurring as subvertical northeast trending discontinuous zone in the center of Bald Mountain" "Rocks of the Adirondacks in Vermont and in the Whitehall, NY area" Diabase dike Metaplutonic Neoproterozoic