Eocene Land Mammals on the Pacific Coast

The Sespe formation comprises a series of sandstones, shales and conglomerate, several thousand feet in thickness, and receives its name from the type locality of its occurrence on Sespe Creek north of the Santa Clara Valley, Ventura County, California. Originally described by Watts [1], this formation has been recognized as furnishing an important stratigraphic record of the early Tertiary in the southern coast ranges with a position between marine sediments of Eocene age and marine sediments of Miocene age. At a number of localities in southern California deposits having the stratigraphic position and lithologic characteristics of the Sespe are designated by that name and are regarded as the correlatives of this formation. Prevailing features which have been noted with regard to the Sespe are (1) the presence of red beds, and (2) the absence of a fossil record.