Geology

• You might be looking for the UC Davis Geology Department.

The geology of Yolo County is in the Great Valley which is generally sedimentary with the exception of volcanic rock in the Sutter Buttes. The Sutter Buttes are not in Yolo County, but are part of the Great Valley. Our soils here are generally quite clayey with varying amounts of silt, they are fantastic in general for agricultural purposes (hence the $300,000,000 Ag economy in Yolo County)

The Coast Range are older sedimentary rocks than the Valley. The nearby Sierra Nevada is mostly granitic rock in the south and more metamorphic rock in the foothills and the north.

For more information, see the the Regional Geologic Mapping Project of the California Geological Survey.

Soils related information on Yolo County can be found either through the NRCS WebSoilSurvey or the UCD Soil-Web Online Soil Survey.

If you're interested in the surface, check out the local geography.