ALLUVIUM AND COLLUVIUM--Clay, silt, sand, and gravel in flood plains, fans, terraces, and
     slopes. Qa
GRAVEL, PEDIMENT, AND FAN DEPOSITS--Mostly locally derived clasts.  Includes some
     glacial deposits along east flank of Wind River Range. Locally includes some Tertiary
     gravels. Qt
GLACIAL DEPOSITS--Till and outwash of sand, gravel, and boulders. Qg
LANDSLIDE DEPOSITS--Locally includes intermixed landslide and glacial deposits, talus, and
     rock-glacier deposits. Qls
DUNE SAND AND LOESS--Includes active and dormant sand dunes.  In northwestern Wyoming
     is chiefly loess (age 12,000-19,000 years). Qs
PLAYA LAKE AND OTHER LACUSTRINE DEPOSITS--Chiefly clay, silt, and fine sand. 
     Includes travertine deposits. Ql
UNDIVIDED SURFICIAL DEPOSITS--Mostly alluvium, colluvium, and glacial and landslide
     deposits.  Primarily in Yellowstone area and Bighorn Mountains. Qu