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The mission of the San Mateo County Historical Association is to inspire wonder and discovery
of the cultural and natural history of San Mateo County.

Object Record

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Catalog Number 2014.009.043
Description Cast of Macoma nasuta, bent-nosed 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. Specimen is a casting of two Macoma nasuta fossil in sediment. Growth lines are visible, highlighted by lighter colored sediment. Overall hue is reddish-brown, indicating the likely presence of iron oxide.
Object Name Shell, Animal
Collection 3D - Paleontology
Title Cast of Macoma nasuta, Bent-nosed Clam Fossil, 1.5-.75 Ma
Date 1.5 - .75 Ma
Kingdom Animalia (Animals)
Phylum Mollusca (Molluscs)
Class Bivalvia (Bivalves)
Order Veneroida (bivalve order)
Family Tellinidae (Bivalve molluscs)
Genus Macoma
Species nasuta
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.
Macoma nasuta (Common name: Bent-nosed Clam) still thrives in the Bay Area.
Dimensions H-1 W-3.375 D-2.375 inches
Search Terms Fossils
Merced Formation
Shellfish
South San Francisco
Subjects Fossils
Marine biology
Shellfish
Shells