The central Oregon coast has a rich geologic history. Here at Beverly Beach you can find fossils from the Astoria Formation deposited during the middle Miocene era which was around 15 million years ago. The type of rock in the Astoria Formation containing these fossils includes siltstone and sandstone compressed with volcanic ash which are gray in colour. The Nye Mudstone is another formation from the Middle Miocene, around 20 million years ago. It also contains fossils; it is composed of clay and finely textured sandstone with a distinct brown colour. It lays in a layer beneath the Astoria formation in the cliffs.
Rocks and fossils from both the Astoria Formation and the Nye Mudstone slowly erode out of the cliffs when wind and waves from storms barrage the coast, and after storms the sea can sometimes pull enough sand from the beaches to expose rock and concretions all the way down to the water line at low tide.
Other rocks found here are primarily basalt, erupted and deposited from a local volcanic cone near Cape Foulweather in the late Miocene.
Miocene-era Beverly Beach was under water, a moderate depth from the shoreline. The water was cold and was host to thick beds of sediment in a western-deepening sea. The bulk of the fauna found here were Foraminifera, or shellfish, but only around a dozen species. Aquatic mammals were also present, as well as lots of fish.
The Astoria Formation is host to many animal fossils including bivalves, gastropods, nautiloids, fish and even mammals. Petrified wood (pictured below) is abundant as well. A well trained eye can spot the brown or black petrified wood fossils among the cobble. Trees giving specimens include oak, alder, myrtlewood and conifers. Sometimes petrified wood loses much of its structure when it is fossilized and may not look like wood - often times the wood is preserved very well and visually they may look the same. If you want to make sure wood is petrified, scratch it with your nail; normal wood is softer, petrified wood is literally rock.
Bivalves, above, are the most common fossil found at Beverly Beach. They have shells divided on a left to right axis and usually the hinge is connected and manipulated by a single muscle. Some of the bivalves found here include clams and scallops. The teredo marine clam is known for boring holes through ancient woods creating interesting petrified wood specimens with little swiss cheese-like tunnels filled with sedementary rock. Teredo wood, pictured below, is plentiful here.
Seen in the photo above are gastropods, or snails. They are relatively commonly found as well. These are distinguished by the whorl of their twisting spiral shells. Gastropod locomotion is from their foot, a fleshy protuberance from their body in the hole of the bottom of the shell. They eat with an armoured tongue that drills through shells of other shellfish creating small holes. Some fossil shells are found with these holes!
Fossil bone, seen above, can be distinguished by their sandy-looking texture compared to the gray or brown surrouding rock. Upon closer inspection, you may see surface bone preserved alongside the inside cellular structure. If a bone is still in its matrix you can see a definite contrast of dark brown bone against the light brown colour of the Nye Mudstone, or a brown bone inside the gray Astoria Formation rock. Bones found here can be ribs, vertebrae, skulls, any bone found in the animal but most of what you find will be rounded by the surf. You can find fossil bone from fish, sharks, seals, sea lions, dolphins, porpoises, and whales. Removing and keeping vertebrate fossils is prohibited without a permit.
Fossils encased in rock are called concretions (above). These occur when an object, such as a shell, bone or piece of wood builds up deposits of sediment around it and over time the sediment hardens and becomes stone. Lots of these concretions are round and look like cannonballs. If you were to break a concretion open there is sometimes a fossil inside. Sometimes there is nothing inside concretions at all, much to the chagrin of rockhounds! The rock attached to fossils is called the matrix, or host rock.
Head to the beach at and around the waypoint and look in the rocks. Do your best to find a fossil or two.
You must answer the following questions:
1. What kind of fossil did you find?
2. What kind of animal do you think this fossil from?
3. What kind of rock do you think is it in? (If it isn't in rock anymore, what kind of rock do you think it eroded out of?)
4. What kind of environment do you think the animal whose fossil you found lived in?
Send your answers privately, do not post your answers in your log!!!
For bonus points, take a picture of yourself with your fossil!
For extra nerd cred, tell me the genus and/or species of your fossil!
PLEASE READ THE FOLLOWING IF YOU ARE GOING TO VISIT THIS LOCATION/LOG THIS EARTHCACHE:
Pay attention to the tide tables before going into the beach and follow the rules on the sign at the beach access.
Do not climb on logs, never turn your back on the ocean and be aware of the waves at all times!
Please only visit this beach during daylight hours when the park is open.
Digging in or climbing on the cliffs along the beach is prohibited.
Most fossils can be found at low tide on sandy beaches, in creek washes, and below the rockier headlands in high-tide rock piles. Fossils found on public beaches may be taken, but they may not be commercially sold without a permit. You cannot legally collect or take fossils from marked “marine gardens” or beaches adjacent to Oregon State, U.S. Forest Service, or BLM parks, campgrounds, and natural areas. This includes Beverly Beach.
Oregon State University’s Hatfield Marine Science Center (in Newport) and the Oregon Museum of Science and Industry (in Portland) are two locations where you’ll find exhibits of fossils discovered on Oregon’s beaches.
Please take note of the Oregon administrative rule for collecting on ocean shores OAR 736-021-0090 (4) (a) (A) regarding removal of rocks and fossils:
"Agates and other non-living items such as shells, stones, and fossils loose on the ground, in small quantities, defined as no more than a one-gallon volume container per person per day; up to three gallons per person per calendar year."
(This is permitted for non-commercial personal use ONLY.)
All photos in this description were taken by and belong to me, except the photo of concretions, which is from Wikipedia commons and is public domain.