Cowles Mountain consists of Jurassic and early Cretaceous metavolcanic and shallow intrusive igneous rocks that are resistant to erosion, and never covered by later Cretaceous and Tertiary sedimentary overburden.
Small plateaus on the south and east slopes are the remnants of an extensive terrestrial, near sea level erosional surface called the Poway Terrace that are now about 1,200 feet (370 m) in elevation.

A prominent former seacliff on the west side rises above a now-dry wave-cut terrace, now mostly covered with suburban developments, at about 600 feet (180 m) in elevation.
Cowles Mountain consists of Jurassic and early Cretaceous metavolcanic and shallow intrusive igneous rocks that are resistant to erosion, and never covered by later Cretaceous and Tertiary sedimentary overburden. Small plateaus on the south and east slopes are the remnants of an extensive terrestrial, near sea level erosional surface called the Poway Terrace that are now about 1,200 feet (370 m) in elevation.
A prominent former seacliff on the west side rises above a now-dry wave-cut terrace, now mostly covered with suburban developments, at about 600 feet (180 m) in elevation.
Cowles Mountain