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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 2014.009.008
Description Euspira lewisii, moon snail 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 snail-shaped, with distinct swirls visible at top of shell. Shell is mostly white, with contrasting patches of varying shades of beige and darker gray sediment. Underside surface is mostly white, with grayish beige colored sediment exposed.
Object Name Shell, Animal
Collection 3D - Paleontology
Title Euspira lewisii, Moon Snail Fossil, 1.5 - .75 Ma
Date 1.5 - .75 Ma
Kingdom Animalia (Animals)
Phylum Mollusca (Molluscs)
Class Gastropoda (Snails, limpets)
Order Achatinoidea (Snails)
Family Naticidae (Moon snails)
Genus Euspira
Species lewisii
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 4/24/2014.
A moon snail feeds upon other snails and bivalves. They wrap their large foot around their prey, making it impossible for its victim to breathe. Moon snails can also drill holes in prey. They soften the shells of clams by secreting acid, and then they drill a hole through the clam using a mouth part called a radula. Once the hole is drilled, they scrape out and eat the clam meat, leaving the rest of the shell intact.
Dimensions H-1.5 W-2 D-1.75 inches
Search Terms Fossils
Merced Formation
South San Francisco
Subjects Fossils
Marine biology