The Torrey Sandstone (Torrey Sand member of Hanna, 1926) crops out continuously from the northern boundary of the area 12 km south to Torrey Pines Golf Course and inland about 10 km. It has a maximum thickness of 60m and is composed cof arkosic sandstone which is white to light brown, medium to coarse grained, subanguiar, and moderately well indurated. It is massive and broadly cross-bedded. The sandstone consists of quartz (85-90 percent), orthsclase (5-10 percent), plagioclase (less than 1 percent), biotite (1-5 percent), and a trace of hematite, epidote, zircon, tourmaline, pyroxene, and amphibole. At the type section at Torrey Pines grade on Highway 101, the contact with the underlying Delmar Formation consists of an alternating gradation between white sandstone beds above the dusky yellow-green fos siliferous claystone beds below. Approximately 15 km to the north, the Torrey Sandstone grades into and is overlain by the Santiago Formation. In Soledad Valley the lower part grades into and is overlain by the Ardath Shale and the upper part by the Scripps Formation (Kennedy and Moore, 1971a). The Torrey Sandstone is believed to have been deposited along a submerging coast on an arcuate barrier beach that enclosed and then later transgressed over Delmar lagoonal sediments. Its deposition was arrested when submergence slowed and the shoreline retreated. Although the Torrey Sandstone contains only a few poorly preserved fossils and fossil casts, its middle Eocene age is firmly established by its interfingering relations hip with the well-dated Ardath Shale.

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

Hanna, M.A., 1926, Geology of the La Jolla quadrangle, California: University of California, Dept. Geol. Sci. Bull., v. 16, p. 1 87-246.
Kennedy, M.P., and Moore, G.W., 1971a, Stratigraphic relations of upper Cretaceous and Eocene formations, San Diego coastal area, California: American Assoc. Petroleum Geologists Bull., v. 55, p. 709-722.