Geology Trip with Judith and Eldridge Moores

Join Eldridge and Judy Moores for day-long, circular road trip through the eastern Coast Ranges, where you will be introduced to the geological history of California’s dynamic landscape.  The trip includes outcrops of upended sedimentary rocks of the Great Valley, various volcanic and metamorphic rocks west of Winters and in Napa Valley, landslides, and strands of the San Andreas Fault. The trip (via caravan) is scheduled for Saturday, August 19, from 8 AM to 5:30 PM.

  • Cost: $60/person (The Moores are hosting this event to support Tuleyome. All funds from ticket sales will go to assist Tuleyome’s conservation efforts in the region.)
  • Number of participants: 25-30
  • CLICK HERE to download a flyer.

Logistics: The field trip group will meet in Davis to form carpools.   Participants will be expected to bring their own picnic lunches and water. Additional information, including the specific meeting place, will be provided to those who enroll. While older teens would enjoy the trip, it is not appropriate for children or animals.

Judy Moores at


The Berryessa Snow Mountain National Monument region’s stunning geology augments its storied history and notable biological diversity. An ancient boundary between the North American Plate and the Farallon Plate descending beneath it is present in the form of the Coast Range Fault. Rocks of the upper plate include Great Valley sedimentary and volcanic rocks overlying remnants of ancient oceanic crust rich in serpentine, a mineral that forms when water reacts with peridotite and similar rocks that originated in Earth’s mantle. The upper plate represents part of the western edge of North America that formed between 140 million and 20 million years ago. Lower plate rocks include the Franciscan Complex: deformed and metamorphosed sedimentary and volcanic rocks that were scraped off the downgoing plate and buried 20 to 30 kilometers beneath the edge of North America, before being uplifted to the surface by erosion. The active San Andreas Fault — a transform fault — developed more recently, modifying the earlier convergent tectonic boundary.

You can read the Moores’ “Earth Magazine” article on the geology of the region HERE.

Note: All participants agree to abide by the terms and conditions of Tuleyome’s waiver of liability which can be seen and downloaded HERE. All participants also understand that photographs will be taken at the event. If you do not wish to be photographed, you must tell the photographer and avoid the cameras’ line of sight.


Starts 8:00 am
Ends 5:30 pm
Location This information will be provided to those to enroll.