Rico and Hermosa Fms

Arkosic sandstone, conglomerate, shale, and limestone. Includes at base in some areas siltstone and shale of Molas Fm or Larsen Quartzite
State Colorado
Name Rico and Hermosa Fms
Geologic age Pennsylvanian
Lithologic constituents
Sedimentary > Clastic > Conglomerate
Sedimentary > Clastic > Mudstone > Shale
Sedimentary > Clastic > Sandstone > Arkose
Sedimentary > Clastic > Siltstone
Sedimentary > Carbonate > Limestone

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

NGMDB product
Counties Archuleta - Dolores - Hinsdale - La Plata - San Juan