Stonerose is the only public fossil digging program in Washington State. Open to all ages, the site gives fossil enthusiasts of all ages the unique ability to unearth 50 million year old plants, insects, and fish, now encased in shale. Best of all, this site is so fossil-rich that visitors are guaranteed to find fossils. Each visitor can keep three fossils per day.
A scientifically important site, the geologic forces that resulted in the fossils at Stonerose are the culmination of a warm temperate habitat unlike any other Eocene environment for which science has found a fossil record.
The area was once an ancient lake. Over many years, layers of sediment built up on the lakebed. Much of this material was powdery ash from volcanic activity which brought about the evolution of many major groups of plants, insects, and fish, which rapidly appeared and diversified.