The Williams Formation is a Mesozoic geologic formation. Dinosaur remains (including hadrosaurid fragments) are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus. In 1996 Gino Calvano found foot bones, two cervical vertebrae, and a phalanx (toe) from a hadrosaur in this formation, along the western base of the Santa Ana Mountains in Orange County, California.
References
Williams Formation Wikipedia(Text) CC BY-SA