Shale, claystone, sandstone, and major coal beds
East: Ashy claystone and sandstone. Includes Castle Rock Conglomerate in region southeast of Denver. Northwest: Ashy claystone in North Park
Includes dune sand and silt and Peoria Loess
Loose to well-cemented sand and gravel
Includes Slocum, Verdos, Rocky Flats, and Nussbaum Alluviums in east, and Florida, Bridgetimber, and Bayfield Gravels in southwest
Includes Broadway and Louviers Alluviums
Includes Piney Creek Alluvium and younger deposits
Pierre Shale--Upper unit
Fox Hills Sandstone
Arkosic sandstone, shale, mudstone, conglomerate, and local coal beds
Laramie Fm and Fox Hills Sandstone
Sandstone, mudstone, claystone, and conglomerate; Denver is characterized by andesitic materials
Sandstone; contains abundant volcanically derived material
Southwest Wyoming: South end of Wind River Range--Siliceous, arkosic, and locally radioactive sandstone, claystone, and conglomerate. Fission-track age about 27 Ma. Recent work suggests that part of these deposits may be of Eocene age. Pliocene and Miocene (as originally defined 2) South Pass Formation. Saratoga Valley--White to greenish-gray tuffaceous sandstone, siltstone, and claystone; locally conglomeratic. North Park Formation; Central Wyoming: Arkosic sandstone, conglomerate, and siltstone; some light-colored tuffaceous radioactive claystone and white cherty limestone. North of Sweetwater River in Granite Mountains--Light-colored tuffaceous radioactive claystone, siltstone, sandstone, and arkose. Moonstone Formation; East Wyoming: Light-colored tuffaceous claystone, sandstone, and conglomerate. Ogallala Formation in Denver Basin.
Silt, sand, sandstone, gravel and conglomerate. Predominantly interfingered fine- to coarse grained, poorly sorted, arkosic, fluvial deposits of light-gray, light-olive-gray, and grayish-green calcareous silt and sand, and locally poorly consolidated conglomerate, sandstone, and siltstone.
White to pale-pink blocky tuffaceous claystone and lenticular arkosic conglomerate.
Mostly locally derived clasts. Includes some glacial deposits along east flank of Wind River Range. Locally includes some Tertiary gravels.
Clay, silt, sand, and gravel in flood plains, fans, terraces, and slopes.