A transitional alluvial to marine sequence; the Eocene Llajas Formation, southern California

The early to middle Eocene Llajas Formation of the southwestern Santa Susana Mountains, Transverse Ranges, in southern California forms a retrogradational system followed by a progradational system. The retrogradational system grades vertically upward from coastal alluvial fan, to shallow-marine, to outer shelf to slope with incised channels. These channels and associated outer shelf to slope facies were subsequently covered by progradational shallow-marine facies. The progradational cycle is incomplete due to erosional truncation by the nonmarine early late Eocene Sespe Formation.