Granitic rock of Mount Princeton batholith, equigranular biotite-hornblende monzogranite interior facies
Granite. Eocene, about 38 to 34 million years old. 2 crags on this site have their map point on it.
What the map says
Light-gray, medium- to coarse-grained, equigranular monzogranite. Average of six modal analyses indicates about 24 percent quartz, 28 percent potassium feldspar, 37 percent plagioclase, 10 percent biotite plus hornblende, and accessory large sphene (easily visible in hand specimen), magnetite, allanite, apatite, and zircon (Shannon, 1988). Predominant phase of the Mount Princeton batholith, forms the major unit along South Cottonwood Creek and Chalk Creek
1:100,000 sheet: Kellogg and others, 2017, U.S. Geological Survey Scientific Investigations Map 3382 (2 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.