The Payton Ranch Limestone is a geologic formation in the Klamath Mountains province (geology) of Northwestern California.USGS.gov: Payton Ranch Geologic Unit
It preserves fossils dating back to the Silurian period of the Paleozoic Era.
It is a Limestone Member of the Silurian Gazelle Formation.
See also
List of fossiliferous stratigraphic units in California Paleontology in California
References