Alamosa Fm: gravel, sand, silt
Includes dune sand and silt and Peoria Loess
Includes metabasalt, metatuff, and interbedded metagraywacke; locally contains interlayered biotite gneiss. Derived principally from volcanic rocks
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.
Gabbro and mafic diorite and monzonite
Includes several named units
Intermediate to felsic compositions
Includes some unclassified glacial deposits