Exploring Oregon Beach Fossils

There's an old saying that finding fossils in Oregon is not about where to look, but where not to look.

- BY ERIC DAVIS

Top, left: Our fossilized mystery mammal bone found at Stonefield Beach (Lane County)

The Oregon Coast and much of the Coast Range was underwater and part of an ancient sea floor. So, marine fossils can be found a significant distance inland from the current shoreline. There are numerous geological formations here and each one holds different specifics and clues about what used to call this place home.

Today, Oregon Coast fossils are mostly known from three formations: Astoria, Nye Mudstone and Coaledo. Astoria is roughly 15 to 20 million-year-old blue-grey sandstone layers mixed with compressed volcanic ash, making up the northern to central coast beaches. Nye Mudstone is up to 20-million-year-old, fine-grained grey sedimentary rock found in areas within the central coast. Coaledo is loosely 25to 30-million-year-old dark ash and sand, found on the south coast stretches of beach. There are handfuls of others in between and inland, containing traces of equally interesting prehistoric life. Here’s what can be found in these formations, the better-known fossil hunting localities and best practices when going rockhounding at the beach.

Top, right: Agatized gastropod fossil from Nehalem (Tillamook County)

KNOW BEFORE YOU GO

One of the first things to do is to have an idea or a visual in your head of what is out there and possible to find. Sometimes what you think you're on the hunt for looks a bit different in reality because of the age or the conditions in which it can found today. Other times, fossils can take you by surprise and you might not think something is a fossil at all when it really is. Be open-minded, question things, and have fun, too.