Fossilized Clam Shell

While visiting Beverly Beach on the Oregon coast last week I collected several treasures.

My wife, Kathy and our son, Chris and I scoured the beach for agates and other semi-precious stones.

Chris enjoys the hobby of rock polishing. He showed us some of the tricks for finding these gems. Our agate treasures are tumbling in the grit for the next 4 weeks.

While pursuing the agates, I also was in the hunt for fossils.

Knocking apart a very hard sandstone rock revealed the embedded clam you can see in the photo.

The stone fragment is sitting on a mirror to show the underside of the clamshell (note: a bit confusing, use imagination). I believe it is from the "Astoria Formation" type rock discussed below.

The fragment of rock is 3 centimeters long; the clam is 2 X 1.5 centimeters.

My crude efforts resulted in a specimen far from perfect, but no less fun for me to liberate a recognizable clam from the petrified heart of a smooth piece of granite-hard sandstone.

Close up view:

Fossils You Can Find on Oregon Beaches
By by Guy DiTorrice.
Edited and laid out by Rick Cooper.
ORESU-G-04-001
© 2004 by Oregon State University.
This publication may be photocopied or reprinted in its entirety for noncommercial purposes.

Oregon's sandy beaches are known for their shells, sand dollars, agates, and jaspers, as well as for a wide variety of Miocene-era marine and mammal-bone fossils.

Geologically speaking, Oregon coast fossils are found in three formations: the Astoria Formation, 15- to 20-million-year-old sandstone layers mixed with compressed volcanic ash; Nye mudstone, up to 20 million years old; and on south coast stretches of beach, Coledo Formation specimens of dark ash and sand, which are 25-30 million years old. These formations of compacted sand, volcanic ash, and river-borne silt are uplifted from the Pacific Ocean floor by geo-plate movement.