This is a large chunk of calcareous sandstone from the Lower Miocene Temblor Formation--it is a coquina, crammed with Turritella gastropods, called Turritella ocoyana; such Turritella coquinas are quite common in the Temblor Formation, exposed in the vicinity of the Kettleman Hills, California; farther east, near Bakersfield, the Middle Miocene portion of the Temblor Formation yields the world-famous Sharktooth Hill bone bed, in which innumerable shark teeth and marine mammal bones are preserved in a rather narrow horizon not more than three feet thick. |