Christine Colasurdo

A former resident of Oakland, Christine Colasurdo now lives in San Francisco. She is the author of Return to Spirit Lake: Journey through a Lost Landscape (Sasquatch Books, 1997). Her work has appeared in California Wild, Audubon, and other publications. She thanks the following people for sharing their knowledge: geologists David Howell and Russ Graymer of the USGS and Doris Sloan of UC Berkeley; botanist Bruce Pavlik at Mills College; and Steve Edwards, director of the Regional Parks Botanic Garden.

Out of an Ancient Sea


The oak-dotted, rounded hills of Contra Costa and eastern Alameda counties are a familiar sight, but do you know how they got to be that way?