Middle and Lower Eocene Rocks

Equivalent to Aycross (Ta) and Wind River (Twdr) Formations. Aycross Formation (Absaroka Volcanic Supergroup: Thorofare Creek Group) - Brightly variegated bentonitic claystone and tuffaceous sandstone, grading laterally into greenish-gray sandstone and claystone. In and east of Jackson Hole contains gold-bearing lenticular quartzite conglomerate. Wind River Formation - Variegated claystone and sandstone; lenticular conglomerate.
State Wyoming
Name Middle and Lower Eocene Rocks
Geologic age Lower Eocene-Middle Eocene
Lithologic constituents
Sedimentary > Clastic > Siltstone (Tuffaceous)
Sedimentary > Clastic > Sandstone (Tuffaceous)
Sedimentary > Clastic > Mudstone > Claystone (Tuffaceous)
Sedimentary > Coal (Lens)
Sedimentary > Clastic > Conglomerate (Lens)
Comments COMU shows age with large arrow bar in both directions in Eocene.
NGMDB product
Counties Fremont