Kelley House docents David and Katy Tahja are rockhounds. Their idea of a perfect day is being out in the middle of no place with interesting rock samples peeking out of an easily accessible creek bed.

Sliced Coprolite, or paleo feces. The Tahjas have coprolites from their collection on view at the Kelley House (Attribution 2.0 Generic CC BY 2.0, Flickr)

Their explorations have taken them to the empty back country of California, Oregon, Nevada, Colorado, and Wyoming, following leads they gleaned from books, maps, websites, government publications, and word-of-mouth.

While both of them took geology in college, neither consider themselves geologists. Says Katy, “We’re wanderers who like pretty rocks. Most of our finds line our garden paths and sidewalks at home and are all mixed up as to where they were picked off the ground.”

The Tahjas are sharing their rocky passion with us as participants in our COASTAL COLLECTIONS exhibit series, where individuals or groups loan us the things they have gathered and treasured over the years. These physical objects, photographs, or other items encompass a wide range of subject matter, all with some kind of cohesive theme. 

Katy and David have brought us some great finds – Geodes, raw Turquoise, and Petrified Wood. But the most unusual sample has to be the smooth round spheres known as Coprolite. For the uninitiated, that’s fossilized dinosaur poop. Each sample is unique, reflecting the varied diet of the ancient animals from whence they came. Colorful stripes and nodules make them a favorite for jewelry-making. Yes, you can wear ancient excrement. 

If the Tahjas could recommend to fellow rockhounds some of their favorite places, they would send you to Richardson Rock Ranch north of Madras, Oregon, on Highway 97. While it’s a digging site that charges a fee, you come away with things called Thundereggs, and the yard of their thrift shop has bins filled with colorful rock from around the world.

Should you want to stay in California, County Highway J-1 turns west off of Interstate 5. The road cuts through levels of uplifted Central Valley sediments that expose Jaspers – yellow, green, and red varieties – that you can scrape out of the hillside with your bare hands. A great summer road trip destination with the kids this summer.

The Tahjas invite the public to contact them at to ask about rockhounding adventures. They also suggest the book “Rockhounding Northern California: A Guide to the Region’s Best Rockhounding Sites,” by Montana Hodges as a good starter’s guide to explorations.

The Kelley House Museum welcomes you on Saturdays and Sundays between 11am and 3pm. Our address is 45007 Albion Street in Mendocino. The Tahja’s rock collection is on view until the end of June, followed by a two-month display of artistic quilt squares depicting the iconic buildings of Mendocino, created by the Ocean Wave Quilters. Contact us at