Arkosic conglomerate, sandstone, and shale
Pierre Shale, undivided
Calcareous shale and limestone
Sandstone and shale
Carlile Shale, Greenhorn Limestone, and Graneros Shale
Shale and sandstone. Includes Farisita Conglomerate in northwestern Huerfano County
Includes metabasalt, metatuff, and interbedded metagraywacke; locally contains interlayered biotite gneiss. Derived principally from volcanic rocks
Arkosic conglomerate, sandstone, and siltstone
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.
Sandstone and shale
Siltstone, sandstone, and conglomerate
Includes Piney Creek Alluvium and younger deposits
Pierre Shale (Kp), Niobrara (Kn), and Carlile, Greenhorn, and Graneros (Kcg) Fms, undivided
Intermediate to felsic compositions
Arkosic sandstone, siltstone, and shale; contains major coal deposits in Raton Basin
Includes several named units
Shale, sandstone, and major coal beds; sandstone
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
Locally includes talus, rock-glacier, and thick colluvial deposits
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
Includes some unclassified glacial deposits
Gabbro and mafic diorite and monzonite
Morrison, Ralston Creek, and Entrada (or Exeter) Fms
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