This report contains the detailed geology of all known active Sonoma County rock quarries. In addition to the geology, information on reserves, material uses, history, and owner's future plans is included where available.

The purpose of this study was to do a reconnaissance of potential major hardrock resources areas in Sonoma County, California. The study is the second part of an overall study of hardrock quarries in the county, and is a component of the Sonoma County . . .