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
Intermediate to felsic compositions
Includes metabasalt, metatuff, and interbedded metagraywacke; locally contains interlayered biotite gneiss. Derived principally from volcanic rocks
Siltstone, sandstone, and conglomerate. Includes Wagontongue Fm (Miocene) in South Park
Includes Broadway and Louviers Alluviums
Includes some unclassified glacial deposits
Includes Slocum, Verdos, Rocky Flats, and Nussbaum Alluviums in east, and Florida, Bridgetimber, and Bayfield Gravels in southwest
Mainly intermediate to felsic compositions; some mafic
Granitic rocks of 1400- and 1700-m.y. age groups, undivided, or, in Taylor River region, rocks with characteristics of Xg but U-Th-Pb zircon ages of Yg
Locally contains minor hornblende gneiss, calc-silicate rock, quartzite, and marble. Derived principally from sedimentary rocks
Leadville Limestone, Williams Canyon Limestone, and one or more of: Fremont Limestone, Harding Sandstone, and Manitou Limestone
Includes many named units
Minturn and Belden Fms
Includes several named units
Gypsum, siltstone, and shale
Early ash-flow tuff of Sawatch Range provenance
Older glacial drift
Locally includes talus, rock-glacier, and thick colluvial deposits
Leadville Limestone, Williams Canyon Limestone , Manitou Limestone, and Sawatch Quartzite
Includes basalts of Hinsdale Fm in San Juan Mountains - Servilleta Fm in San Luis Valley and many other occurrences
Rhyolitic intrusive rocks and flows of late-volcanic bimodal suite
Gabbro and mafic diorite and monzonite
Intra-ash flow andesitic lavas