Grazing Allotment Crag

Rock, from the geologic map

Mountain valley alluvium — gravel, sand, alluvium. Quaternary, younger than 126,000 years.

Pebbly to bouldery gravel, sand, and minor deposits of silty alluvium in stream channels, floodplains, and low terraces along courses of major and tributary streams in the mountains west of the foothills hogback belt and along the Laramie River near the northwest corner of the quadrangle. Unit Qva locally includes outwash deposits (Qgp) downstream from till of Pinedale age (Qtp), small fans deposits (Qf) and minor deposits of colluvium (Qc) along valley margins, as well as organic-rich sediments (Qo) in bogs, fens, marshes, and meadows. Deposits of unit Qva, near cirques in the Medicine Bow Mountains, locally may include outwash deposits of post-Pinedale age. Unit is chiefly present along the Cache la Poudre River, Laramie River, and their tributaries. Outwash deposits are a potential source of coarse aggregate. Low-lying deposits are prone to periodic flooding. Estimated thickness is 3–9 m

This is the map unit under this crag's map point, read from the 1:100,000 sheet (Workman and others, 2018, U.S. Geological Survey Scientific Investigations Map 3399). The point can be a few hundred metres from the rock, a cliff often stands on the line between two units, and at that scale a line on the map is about 100 m wide on the ground, so the wall itself may be the neighbouring unit. Every crag on this unit: Mountain valley alluvium. Geology data: Macrostrat (CC BY 4.0), serving USGS and Colorado Geological Survey maps.