Oregon Fossil Guy Trading Depot
Bivalve Fossils (clams) have shells divided on a left-right axis and are generally hinged together with a single adductor muscle. Here’s a list of the most common bivalve fossil species on Oregon’s coast and a brief description of each:
Click To Enlarge	Anadara devincta—Oregon’s most common marine fossil, similar in appearance and shape to the cockles of today (see photo at right). Anadara devincta isan indicator fossil worldwide for Miocene-age formations.
	Katherinella angustri—another common clam fossil with a broad, smooth-patterned shell, often found agatized, or translucent.
Clike To Enlarge	Macoma arctata—a thin, flat shell, often having a hole drilled by snails (which then ate the clam inside).
	Chione ensifera—a shell with a cross-hatched pattern, similar to the steamer clams available in restaurants.
Clike To Enlarge	Panopea arupta—a very large shell, measuring over four inches across.
	Patinopectin/Vertipectin—a large scallop shell, found whole in flat, round concretions, sometimes split by nature, often held in seawalls.
Common Miocene gastropods making Oregon’s coast their home include:
	Gastropods (snails): While clams are the larger and more populous of Oregon’s Miocene marine fossils, gastropods are frequently found, especially inconcretions. For some, the attraction of gastropods results from the artistic 180° twist the shell makes during its growth, called torsion. Most gastropods—herbivores and carnivores—use an armored tongue, or “radula,” as a tool to drill through shells into their meals.
	Bruclarkia oregonensis—a squatty shaped shell, accented with delicate whorls.
	Nassarius arnoldi—a shell with short and slender whorls and artistic ribs
Click To Enlarge	Musashia indurata—a very large shell, nearly six inches long, seldom found whole.
	Ficus modesta—a well-rounded shell with a fig-like shape and delicately lined whorls.
Click To Enlarge	Turritella oregonensis—a shell with high spires, in a tightly curved design, often found in groups.
Click To Enlarge	Crepidula praerupta—an extinct, androgynous, clawlike snail, which moved incolonies linked together.
Click To Enlarge	Chlorostoma pacificum—a shell with a short, rounded design and a well-defined whorl.
Click To Enlarge	Calicantharus carlsoni—similar in look to modern whelks, often fossilized with a Membranipora coat (similar to moss on a tree or lichen on a rock).
Click To Enlarge	Dentalium schencki—sometimes known as a “tusk shell”—look for “white drinking straws” in brown or gray rocks.
Wood and Bone Fossils:
Click To Enlarge	In addition to abundant marine fossils, Oregon’s coast offers a wide variety of petrified woods. As ocean currents moved along the shoreline and rivers ran into the Pacific Ocean, wood species from other regions were deposited on Oregon’s beaches.
Click To Enlarge	Teredo wood appears as brown to black rocks, usually rounded at the ends with a “Swiss cheese” look to them. Fossilized casings from the Teredo marine clam created the pattern when the Teredo, in its larval form, ate its way through chunks of ancient wood. These colonies of small larvae never cross each other’s borings, making each piece unique in design and appearance.
Click To Enlarge	Other petrified woods are light tan to carbonized black, frequently found in sizes ranging from one inch to two feet across. Look for a dull sheen on wet rocks with parallel wood grain patterns. Softwood species of pines and some hardwoods, including alder, myrtlewood, and oak, as well as petrified palm, are also found on Oregon beaches.
Click To Enlarge	An occasional fossilized leaf impression can be found on or in coastal rocks, recognizable as elm, alder, and Oregon Grape—Mahonia repens.
	Petrified wood pieces are also often found in concretions of rounded mudstone or hard gray volcanic ashballs. Sometimes split in half by nature, inside these concretions is often carbonized or fossilized wood that was once carried downstream from the Cascade Mountains. Crabs are one type ofarthropod found inside concretions when split open—claws, legs, and occasionally whole crabs.
Click To Enlarge	Another genre of fossil found on Oregon’s coast is mammal bone. Usually deposited in hardened sandstone, bone is as abundant as Teredo wood and Anadara shells. Look for light brown or gray rocks with rounded edges and adarker edge or center, which is usually bone.
Click To Enlarge	Careful matrix removal can expose identifiable fossilized bone, including vertebrae, ribs, jaw bones, joints, and skulls, which may be from prehistoric whales, dolphins, porpoises, sea lions, or seals.