The Mt. Eden Formation is a geologic unit in Riverside County, California, that preserves fossils from the Neogene period and appears in the layered exposures of the San Timoteo Badlands beneath the San Timoteo Formation. Paleontologist Childs Frick first outlined this stratigraphy in 1921, dividing the badlands into the Potrero Creek deposits, the San Timoteo Formation, and the Eden beds. The name derived from a large schist hill west of the San Jacinto quadrangle. By 1931, Mt. Eden Formation had become the accepted name, while Eden beds fell out of use and the Potrero Creek deposits were no longer recognized separately.