Chatsworth Formation

The Chatsworth Formation is a Cretaceous period sandstone geologic formation in the Simi Hills and western Santa Susana Mountains of southern California.

It is found in western Los Angeles County and eastern Ventura County. The formation's thickness can be more than 610 m.

Fossils
The sedimentary marine formation preserves fossils dating from the Middle Campanian to Early Maestrichtian epochs of the Cretaceous period. It has diverse molluscan faunas.

The most common taxa are:
 * ringiculid Biplica
 * naticids Gyrodes and Euspira
 * trochid Atira
 * aporrhaids Anchuras and Lispodesthes
 * turritellid Turritella
 * perissityid Perissitys