Fossil Cockles

On Saturday (31 October), Shara and I spent part of the day at the Mid-Michigan Rock Club annual show.  We left with several sample to use in classroom presentations and for home display - sulfur from Maybee, MI, a chunk of native copper and quartz from the Upper Peninsula, and a large piece of gypsum.

My favorite purchase of the day was this...

Fossil Cockles from the Pliocene Epoch

These are fossils of an extinct species of cockle (clam) named Clinocardium meekianum.  The fossils are from a rock formation known as the Rio Dell Formation in coastal Humboldt County, CA and date to the Pliocene Epoch (5.33 to 2.58 million years ago).  Each individual shell measures approximately 2.5 to 3.0 inches (6.35 to 7.62 centimeters) across.  The group measures about 6 inches by 7 inches.

The underside of the sample

Rather than being used in classroom presentations, this specimen is destined for a shelf at home next to several other fossils.