NPet
N$t
Troublesome Formation (upper Miocene to upper Oligocene)
Xmg
Migmatitic biotite schist and gneiss (Paleoproterozoic)
Qva
Valley-floor alluvium (Holocene and late Pleistocene?)
Qac
Alluvium and colluvium, undivided (Holocene and late Pleistocene)
Xig
Interlayered gneiss (Paleoproterozoic)
Qcc
Clayey-silt matrix colluvium (Holocene to middle? Pleistocene)
Qg2
Gravelly stream-terrace alluvium unit 2 (late and middle Pleistocene)
Qsw
Sheetwash deposits (Holocene and late Pleistocene)
Qg1
Gravelly stream-terrace alluvium unit 1 (late Pleistocene)
af
Artificial-fill deposits (latest Holocene)
Qg3
Gravelly stream-terrace alluvium unit 3 (middle Pleistocene)
Qg5
Gravelly stream-terrace alluvium unit 5 (middle Pleistocene)
Qsa
Sheetwash deposits and valley-floor alluvium, undivided (Holocene and late Pleistocene?)
Qls
Landslide deposits (Holocene to middle? Pleistocene)
Qti
Till of Pinedale age and till of Bull Lake age, undivided (late and middle Pleistocene)
Qcs
Sandy matrix colluvium (Holocene to middle? Pleistocene)
Qp2
Higher pediment deposits (late and middle Pleistocene)
Qf
Fan deposits (Holocene and late Pleistocene)
Qg4
Gravelly stream-terrace alluvium unit 4 (middle Pleistocene)
Qtb
Till of Bull Lake age (late and middle Pleistocene)
Qp1
Lower pediment deposits (late Pleistocene)
Xhc
Hornblende gneiss and calc-silicate gneiss (Paleoproterozoic)
Qg7
Gravelly stream-terrace alluvium unit 7 (middle or early Pleistocene)
Qg6
Gravelly stream-terrace alluvium unit 6 (middle Pleistocene)
Qgd
Gravelly stream alluvium and diamicton, undivided (middle Pleistocene)
Qg8
Gravelly stream-terrace alluvium unit 8 (middle or early Pleistocene)
Pet
P$
Rhyolite tuff (Oligocene)
YXg
Granodiorite and monzogranite (Mesoproterozoic or Paleoproterozoic)
Qta
Talus deposits (Holocene to middle? Pleistocene)
Qtp
Till of Pinedale age (late Pleistocene)
YXp
Pegmatite (Mesoproterozoic or Paleoproterozoic)
QNg
Old gravelly stream alluvium (early Pleistocene or Pliocene)
Xgd
Foliated granodiorite, tonalite, and diorite gneiss of the Routt Plutonic Suite (Paleoproterozoic)
Kd
Dakota Group (Lower Cretaceous)
Jm
Morrison Formation (Upper Jurassic)
Yp
Pegmatite of the Berthoud Plutonic Suite (Mesoproterozoic)
Cataclastic rock
Ym
Monzogranite and granite of the Berthoud Plutonic Suite (Mesoproterozoic)