Ladd FormationThe Ladd Formation is a Mesozoic geologic formation located in Orange County, California.PaleofaunaDinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus. In 1927 Bernard Nettleton Moore found a hadrosaur maxilla with teeth while searching for ammonites in the formation. In 1950 Marlon V. Kirk found a plesiosaur centrum. In 1978 Robert Drachuk, also while searching for ammonites, collected a hadrosaur cranial fragment from a limestone concretion. In 1992 Robert D. Hansen found the distal tibia of a hadrosaur.