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The mission of the San Mateo County Historical Association is to inspire wonder and discovery
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Object Record

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Catalog Number 2014.009.040
Description Panopea generosa, geoduck clam fossil dating from between 1.5 million years ago to .75 million years ago commonly found at low tide in littoral (sandy and muddy bottom) or sub-littoral (open bay, muddy marine) zones. Fossil specimen is oval-shaped. Top and bottom shells of clam are still attached at the ligament. Growth rings are visible, but not easily detected due to its uneven surface. Overall reddish hue indicates the likely presence of iron oxide. Band of dark brown across the middle of the specimen is sediment between the shells.
Object Name Shell, Animal
Collection 3D - Paleontology
Title Panopea generosa, Geoduck Clam Fossil, 1.5-.75 Ma
Date 1.5 - .75 Ma
Kingdom Animalia (Animals)
Phylum Mollusca (Molluscs)
Class Bivalvia (Bivalves)
Order Myoida (Saltwater clams)
Family Hiatellidae (Small saltwater clams)
Genus Panopea
Species generosa
Inscription Text none
Provenance Fossils taken from Merced Formation collected at Westborough Boulevard at Highway 280 in the late 1970s or early 1980s. (See Yancey 1978, Fig. 2: Artifacts taken from E Stratified Section/D-5929). Most specimens (especially clams) in this collection are not extinct and can still be found in the Bay Area.
Notes Retired Geologist Ken Lajoie identified on 4/8/2014.
Panopea generosa (Common name: Geoduck Clam) still thrives in the Bay Area.
Dimensions H-1.625 W-3.5 D-1.75 inches
Search Terms Fossils
Merced Formation
Shellfish
South San Francisco
Subjects Fossils
Marine biology
Shellfish
Shells