Geology of the San Francisco Bay Region by Doris Sloan Have you ever wondered about the rocks beneath your feet, where they came from, or how they got here? This book, part of the California Natural History Guides series, provides a great introduction to the geology of the Bay Area.

This book covers the different rock formations in the area and the geological process that brought them to their present state. It is not excessively technical in its presentation: one of the nice things about the book is how it provides a general introduction to geology as it discusses Bay Area's geological formations.

Another excellent feature is the abundance of illustrations, photos, and maps. It is one thing for the book to talk about how the soil in parts of San Francisco has settled over the years, causing buildings to sink. Adding a photo of a building that has sunk below street level as a result of this settlement adds an extra dimension to the reader's understanding.

This is a great introduction to the geography and the geology of the Bay Area.