Young stream-channel and overbank alluvium
Holocene, younger than 12,000 years. 6 crags on this site have their map point on it.
What the map says
Mostly pebbly sand and poorly sorted, clast-supported, pebble, cobble, and, locally, bouldery gravel in a sandy matrix. Unit locally may include thin, organic-rich layers. Clasts commonly are sub- angular and subrounded and consist of Proterozoic igneous and metamorphic rocks, Cretaceous and Tertiary intrusive rocks, and, in Arkansas River channel, Paleozoic sedimentary rocks (mostly Cambrian quartzite). Deposits form streambeds and adjacent flood plains, fill channels, and underlie low terraces less than about 2 m above present stream level. Low-lying areas are prone to periodic erosion and (or) deposition. Locally includes minor amounts of colluvium and small fan deposits; locally may include outwash gravel of Pinedale glaciation (Qgp). Estimated thickness is 5–10 m Lithology: alluvium.
1:100,000 sheet: Kellogg and others, 2017, U.S. Geological Survey Scientific Investigations Map 3382 (6 crags). A contact line at that scale is about 100 m wide on the ground.
Served by Macrostrat (CC BY 4.0). The wording is the map's own, quoted as a fact about the mapped unit, not about any one wall.