Post-Piney Creek Alluvium
Holocene, younger than 12,000 years. 5 crags on this site have their map point on it.
What the map says
Dark-gray humic, sandy to gravelly alluvium containing scattered plant remains. Underlies flood plains of major streams and terraces less than 10 feet (3 m) above stream level. Underlain by older alluvial gravel in large valleys. Thickness is from 5 to 1
1:100,000 sheet: Colton, Roger B., 1976, U.S. Geological Survey Geologic Investigations Series I-855-G (5 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.
Boulder
- Ghost Crag3 routes · Boulder Canyon · 5,942 ft · granodiorite (Boulder Creek Granodiorite) (another source)
- Rock Island II2 routes · Boulder Canyon · 5,621 ft · granodiorite (Boulder Creek Granodiorite) (another source)
- Red Lyin' Slab1 route · Boulder Canyon · 5,826 ft · granodiorite (Boulder Creek Granodiorite) (another source)