Potassic basalt (shoshonite) lava flows
Basalt & volcanic. Paleocene, about 66 to 56 million years old. 1 crag on this site has its map point on it.
What the map says
Dark-gray, porphyritic flow rock containing small pheonocrysts of augite, plagioclase, magnetite, and olivine in a fine-grained matrix. Called mafic latite by Van Horn (1976), although only upper flows are latitic; basal flow is a trachytitic basalt. Formerly mapped as three flows on North Table Mountain and two flows on South Table Mountain (Van Horn, 1976); four total flows now recognized (Drewes, 2004). Clinkery bases and vesicular tops are visible, except on upper flow where top is eroded. Locally forms prominent cliffs. Cavities at some localities contain a variety of zeolite minerals (Ellemeier, 1947). Flows most likely erupted from Ralston Buttes area, about 5 km north of Golden. Interlayered with and considered here as members of Denver Formation. 40Ar/39Ar age of upper flow is 63.9±1.2 Ma (Obradovich, 2002). Flows are as thick as 30 m where they filled channels
1:100,000 sheet: Kellogg and others, 2008, USGS Geologic Investigations Series 3000 (1 crag). 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.