The Cabrillo Formation, the uppermost unit of the Rosario Group, is exposed on the Point Loma Peninsula from the southern tip north to Sunset Cliffs. At Pacific Beach in the sea cliffs, it is exposed from 300 m south of False Point to Bird Rock on the north and at La Jolla in an S-shaped belt around the noses of the Pacific Beach syncline and Mount Soledad anticline. In the sea cliff at its type section 250 m east of the new Point Loma lighthouse, it consists of massive medium-grained sands tone and cross-bedded cobble conglomerate containing fresh plutonic and metavolcanic clasts but lacking red porphyritic rhyolite-tuff cobbles characteris tic of nearby Eocene rocks. Throughout the mapped area, the Cabrillo Formation conformably overlies the Point Loma Formation. The formation is 81 m thick at its type locality, where it is unconformably overlain by Pleistocene deposits. Along the sea cliff at False Point, it has a thickness of 170 meters. A clam from the east flank of Mount Soledad within the lower 5 m of the Cabrillo Formation has been identified as "Pharella" alta (Gabb) and assigned to the Maestrichtian (L. Saul, written communication, 1969). The Cabrillo Formation correlates with the upper part of the Forrnacion Rosario of Beal (1924) in northern Baja California and possibly with the upper part of the Williams Formation in the Santa Ana Mountains.

Source - Geology of the eastern San Diego metropolitan area, California (Del Mar, La Jolla, Point Loma, La Mesa, Poway, and SW 1/4 Escondido quadrangles), 1975, California Div. Mines and Geol. Bull. 200, Section A, by Michael P. Kennedy

References

Beat, C.H., 1924, lnforme sobre la exploracion geologica de la Baja California: Boletin Petroleo, v. 17, p. 417-473.