MIOCENE SHARK TOOTH HILL LOCALITY, KERN COUNTY, CALIFORNIA

Shark Tooth Hill is a very rich Miocene fossil locality in the Round Silt Member of the Temblor Formation, of Kern County, California. The fossils occur in well sorted, medium grained sandstone. University of Wisconsin-River Falls (UWRF) received approximately 250 fossils from the Shark Tooth Hill locality, from private collector, James Jones. The UWRF collection was washed, sorted, identified, and curated. To date, fourteen species have been identified in the collection, totaling 113 teeth. Twelve of the species are sharks; six species that are extinct and six extant species. 46.9% of the collection identified is apart of the Lamnidae family with four species of mako sharks. These species match that of the Buena Vista Museums Fauna list circulated 2003: Isurus planus, Isurus hastalis, Isurus retroflexus, and Isurus desori. Therefore, the UWRF collection has a complete representation of the Lamnidae family from Shark Tooth Hill. Two rare species are represented in the UWRF collection: Family Megachasmidae (mega-mouth shark) and Hemipristis serra (snaggle-tooth shark), each with one tooth (representing .90% of the total identified collection). The other two species of the fourteen are that of a ray and marine mammal. Family Myliobatidae (eagle bat rays) represents 5.3% of the identified collection with a total of 6 teeth. Squalodon errabundus (porpoise) represents .90% of the collection with one tooth. With the presence of ray teeth it can be concluded that Kern County was a shallow ocean bay fifteen million years ago. Rays and skates do not inhabit depths greater than 200 feet. The presence of bottom dwellers such as the angel shark and the presence of shorebird fossils also prove that the area had been a shallow sea.