The San Francisquito Formation is a marine geologic unit in northern Los Angeles County, California, exposed in places including San Francisquito Canyon in the Sierra Pelona Mountains and along the northwestern side of Devil's Punchbowl gorge in the San Gabriel Mountains. Deposited from the Late Cretaceous into the Early Paleocene, it spans the transition from the Mesozoic Era into the early Cenozoic. It rests on the crystalline rocks of the San Gabriel Basement Complex and is overlain by younger formations. Lying between the San Andreas Fault and the Devil's Punchbowl Fault, it helps define the region’s complex mountain landscape and preserves Paleogene fossils within southern California’s geologic record.