SUMMIT STORIES  Spring is a great time to visit Mount Diablo State Park. If you go to the top, have a look at the rocks used to build the summit visitor center.  You can easily see fossils of oysters and clams—and, in the sand in between, clues to geologic history of the entire Bay Area. 

From a tour of the Mary Bowerman Loop presented by Mount Diablo Interpretive Association in partnership with Save Mount Diablo.