Includes many named units
Includes several named units
Intra-ash flow andesitic lavas
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
Includes basalts of Hinsdale Fm in San Juan Mountains - Servilleta Fm in San Luis Valley and many other occurrences
Locally includes talus, rock-glacier, and thick colluvial deposits
Ash-flow tuff of late-volcanic bimodal suite
Intra-ash flow quartz latitic lavas
Morrison, Wanakah, and Entrada Fms
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)
Sandstone, shale, and conglomerate. In northwest and west-central: Lower Cretaceous. In southwest: Lower and Upper Cretaceous.
Quartzite, conglomerate, and interlayered mica schist
Arkosic sandstone, conglomerate, shale, and limestone. Includes at base in some areas siltstone and shale of Molas Fm or Larsen Quartzite
Rhyolitic intrusive rocks and flows of late-volcanic bimodal suite
Quartzite, slate, and phyllite
Includes Broadway and Louviers Alluviums
Includes metabasalt, metatuff, and interbedded metagraywacke; locally contains interlayered biotite gneiss. Derived principally from volcanic rocks
Intermediate to felsic compositions
Older glacial drift
Parting Fm: quartzite and shale.
Pictured Cliffs Sandstone and Lewis Shale
Red siltstone, shale, sandstone, and limestone-pellet conglomerate
In northwest and west-central: Major coal beds in lower part; Rollins Sandstone Member at base in Delta, Gunnison, and Pitkin Counties. In southwest: sandstone and shale.
Elbert Fm: shale and sandstone.
Alkalic and mafic rocks in small plutons, and diabase and gabbro dikes
Arkosic sandstone, siltstone, and conglomerate
South-central: Arkosic sand and bouldery gravel of Echo Park Alluvium. Southwest: includes Telluride Conglomerate and Blanco Basin Fm (arkosic mudstone, sandstone, and conglomerate)
Includes Piney Creek Alluvium and younger deposits