Intra-ash flow andesitic lavas
Includes metabasalt, metatuff, and interbedded metagraywacke; locally contains interlayered biotite gneiss. Derived principally from volcanic rocks
Quartzite, slate, and phyllite
Arkosic sandstone, siltstone, and conglomerate
Includes several named units
Arkosic sandstone, conglomerate, shale, and limestone. Includes at base in some areas siltstone and shale of Molas Fm or Larsen Quartzite
Includes many named units
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
Includes some unclassified glacial deposits
Morrison, Wanakah, and Entrada 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
South-central: Arkosic sand and bouldery gravel of Echo Park Alluvium. Southwest: includes Telluride Conglomerate and Blanco Basin Fm (arkosic mudstone, sandstone, and conglomerate)
Elbert Fm: shale and sandstone.
Red siltstone, shale, sandstone, and limestone-pellet conglomerate
Includes Broadway and Louviers Alluviums
Dakota Sandstone or Group
Locally includes talus, rock-glacier, and thick colluvial deposits
In northwest and west-central: Intertongues complexly with units of overlying Mesaverde Group or Fm; lower part consists of a calcareous Niobrara equivalent and Frontier Sandstone and Mowry Shale Members; in areas where the Frontier and Mowry Members (Kmfm), or these and the Dakota Sandstone (Kfd) are distinguished, map unit (Km) consists of shale above Frontier Member. In Southwest: Lower part contains Juana Lopez Member (Kmj)
Parting Fm: quartzite and shale.
Rhyolitic intrusive rocks and flows of late-volcanic bimodal suite
Intermediate to felsic compositions