Paleontology and geology
Outcrops of Jurassic-age rocks occur in the accreted terrane along the border with Oregon and southern Washington. These rocks have been somewhat metamorphosed and were formed mostly in deepwater marine environments. Fossils from these rocks include a fair number of ammonites and oysters and one belemnite. Jurassic rocks in the southeastern part of the state are mostly shallow marine and have a variety of often poorly preserved fossils, including oysters, scallops, crinoids (especially segments of star-shaped crinoid stems), sea urchin spines, ammonites, belemnites, and corals. Interestingly, the presence of raindrop impressions suggests that some of the sediments were either terrestrial or very near-shore and exposed during low tides.