Fossil Hawk leg-
McKittrick Tar Pits, Kern County, California.
Pliestocene epoch.
Leg is 28 cm fully extended.
The McKittrick Tar Pits (also McKittrick Oil Seeps and McKittrick Brea Pits) are a series of natural asphalt lakes situated in the western part of Kern County in southern California. The pits are the most extensive asphalt lakes in the state.  The McKittrick Tar Pits are one of the five natural asphalt lake areas in the world, the others being Tierra de Brea in Trinidad and Tobago, Lake Guanoco in Venezuela and the Rancho La Brea Tar Pits (Los Angeles) and Carpinteria Tar Pits (Carpinteria) both also located in the US state of California.
The creation of an asphalt lake is related to deep faults, often between two tectonic plates. In connection with motion along the plates or subduction, pressure is created against underlying oil source rock, in this case the Monterey Formation.