Jd
Bedrock
Metamorphic
Bedding
Late Triassic and Early Jurassic
Gray
crystalline diabase
Diabase dikes and sills (Late Triassic and Early Jurassic); Gray, medium grained, massive, crystalline diabase
Diabase dikes and sills (Early Jurassic and Late Triassic)
JTRtm
Thermally metamorphosed rocks (Lower Jurassic and Upper Triassic); Variegated fine-grained hornfels with porphyroblasts
hornfels with porphyroblasts
Thermally metamorphosed rocks (Lower Jurassic and Upper Triassic)
TRbg
Bull Run
Chatham
Groveton Member; Gray and brown siltstone and sandy shale
Gray and brown
siltstone and sandy shale
Chatham Group Groveton Member of the Bull Run Formation (Upper Triassic)