Alamosa Fm: gravel, sand, silt
Includes many named units
Includes several named units
Includes Piney Creek Alluvium and younger deposits
Intra-ash flow andesitic lavas
Includes basalts of Hinsdale Fm in San Juan Mountains - Servilleta Fm in San Luis Valley and many other occurrences
Intra-ash flow quartz latitic lavas
Locally includes talus, rock-glacier, and thick colluvial deposits
Volcaniclastic conglomerate interbedded with basalt flows of Hinsdale Fm (Tbb) on east flank of San Juan Mountains. Grades laterally into Santa Fe Fm of San Luis Valley
Includes Slocum, Verdos, Rocky Flats, and Nussbaum Alluviums in east, and Florida, Bridgetimber, and Bayfield Gravels in southwest
Rhyolitic intrusive rocks and flows of late-volcanic bimodal suite
Intermediate to felsic compositions
Includes some unclassified glacial deposits