Pierre Shale--Middle unit

In Boulder-Fort Collins area, contains Richard, Larimer, Rocky Ridge, Terry, and Hygiene Sandstone Members; elsewhere shale between zones of Baculites reesidei and B. scotti
State Colorado
Name Pierre Shale--Middle unit
Geologic age Cretaceous
Lithologic constituents
Sedimentary > Clastic > Mudstone > Shale
Sedimentary > Clastic > Sandstone

Tweto, Ogden, 1979, Geologic Map of Colorado: U.S. Geological Survey Special Geologic Map, scale 1:500,000.

NGMDB product
Counties Boulder - Cheyenne - Crowley - Douglas - El Paso - Fremont - Jefferson - Kiowa - Kit Carson - Larimer - Lincoln - Pueblo