Locally contains minor hornblende gneiss, calc-silicate rock, quartzite, and marble. Derived principally from sedimentary rocks
Includes some unclassified glacial deposits
Pierre Shale, undivided
Includes metabasalt, metatuff, and interbedded metagraywacke; locally contains interlayered biotite gneiss. Derived principally from volcanic rocks
Includes Boulder Creek -M.Y. AGE GROUP (AGE 1650-1730 M.Y.)--Includes Boulder Creek, Cross Creek, Denny Creek, Kroenke, Browns Pass, Powderhorn, Pitts Meadow, Bakers Bridge, and Tenmile Granites, Quartz Monzonites, or Granodiorites; also, unnamed granitic rocks
Mainly intermediate to felsic compositions; some mafic
Arkosic sandstone, conglomerate, shale, and limestone. Includes Madera Fm and Sharpsdale Fm of Chronic (1958) in Sangre de Cristo Range and Gothic Fm of Langenheim (1952) in Elk Mountains. Other units of Middle Pennsylvanian age.
Consists of Niobrara Formation (Kn) and either Benton Shale or Carlile, Greenhorn, and Graneros Fms (Kcg)
Arkosic sandstone, siltstone, conglomerate, and local limestone
Intermediate to felsic compositions
Includes Silver Plume, Sherman, Cripple Creek, St. Kevin, Vernal Mesa, Curecanti, Eolus, and Trimble Granites or Quartz Monzonites; also, San Isabel Granite of Boyer (1962) and unnamed granitic rocks
Older glacial drift
Variegated claystone, mudstone, sandstone, and local beds of limestone
Dakota and Morrison Fms
Locally includes talus, rock-glacier, and thick colluvial deposits
Includes Broadway and Louviers Alluviums
Dakota Sandstone or Group
Includes Piney Creek Alluvium and younger deposits
Siltstone, sandstone, and conglomerate. Includes Wagontongue Fm (Miocene) in South Park
Leadville Limestone, Williams Canyon Limestone , Manitou Limestone, and Sawatch Quartzite
Mainly of intermediate compositions
Sandstone and siltstone; in Middle Park
Dakota, Purgatoire, Morrison, Ralston Creek, and Entrada Fms in southeast. Dakota, Morrison, and Entrada Fms in central mountains. Dakota, Burro Canyon, Morrison, Wanakah, and Entrada Fms in Gunnison River area. Dakota, Morrison, Curtis, And Entrada Fm
Red siltstone, sandstone, and limestone-pellet conglomerate