You Will Not Believe What’s Hiding In These Oregon Rocks‼️😱 If you’re looking for fossils in the Astoria Formation, don’t just look for perfect shells sitting on the beach. A lot of the best fossils are hiding as weird shapes, ridges, grooves, textures, and broken pieces inside ancient marine rock. This formation is made from old ocean sediment, including sandstone, silt, and volcanic ash, and it preserves marine life from roughly 15 to 20 million years ago along the Oregon Coast. Here’s how to