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Clams, Snails, and Squid: Phylum Mollusca, Class Pelecypoda

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Phylum Mollusca
Class Pelecypoda
Pelecypods have two shells, or bivalves, that protect the soft parts of the animal. The valves are generally of equal size (except in groups like the oysters) and shape and are hinged at the back. Some types, such as oysters, live in large groups that create beds or low-relief banks of shells, where the animals feed by filtering plankton and organic debris from the water. Other bivalves burrow through the mud or swim about in search of debris to eat. Many bivalve fossils in Delaware are preserved as steinkerns. Pelecypods are abundant in the spoils from the Mount Laurel Formation on both sides of the Canal in the vicinity of Reedy Point.

Reference(s): 

Unless otherwise noted, photographs and figures are from DGS Special Publication No. 18, by E. M. Lauginiger, 1988.

Photo Gallery
Ostrea mesenterica<br>Exogyra ponderosa - occurs in the Marshalltown Formation, the Englishtown Formation, and the Merchantville Formation<br>Cretaceous Pelycypod illustrations from Page 16, DGS Special Publication No. 19, 1992.
Nemodon enfaulensis<br>Cymella bella<br>Cretaceous Pelycypod illustrations from Page 15, DGS Special Publication No. 19, 1992.
1, 2. Exogyra cancellata - specimens from the Mount Laurel Formation<br>3, 4. Pyncnodonte mutabilis - specimens from the Mount Laurel Formation, also occur in the Marshalltown Formation<br>5, 6. Ostrea (Lopha) falcata - specimens from the Mount Laurel Formation, also occur in the Marshalltown Formation<br>
1. Neithea quinquecostata - specimen from the Mount Laurel Formation, also occurs in the Marshalltown Formation and the Merchantville Formation<br>2. Trigonia sp. - specimen from the Mount Laurel Formation, also occurs in the Marshalltown Formation<br>3. Anomia sp. - specimen from the Mount Laurel Formation, also occurs in the Marshalltown Formation and the Merchantville Formation<br>Plus More
1. Anomia sp. - specimen from the Mount Laurel Formation, also occurs in the Marshalltown Formation and the Merchantville Formation<br>2. Nemodon grandis sohli - specimen from the Mount Laurel Formation<br>3, 4. Gryphaeostrea vomer - specimens from the Mount Laurel Formation, also occur in the Marshalltown Formation<br>5. Nemodon grandis sohli - specimen from the Mount Laurel Formation<br>Plus More
3. Gervilliopsis ensiformis - specimen from the Merchantville Formation <br>Cretaceous Pelecypod photograph from Plate I, DGS Report of Investigation No. 21, by T. E. Pickett, 1972.
All specimens from the Biggs Farm locality within the Mount Laurel Formation<br>1. Nuculana pittensis<br>2. Nuculana stephensoni<br>3. Nemodon enfaulensis<br>4. Nemodon grandis Sohli<br>5. Postligata crenata<br>6. Pteria sp.<br>7. Lucina parva<br>8a,b. Ostrea mesenterica?<br>9. Protocardia parahillana<br>10. Isocardia bulbosa<br>11. Solyma sp.<br>12a,b. Tellina georgiana<br>Cretaceous Pelecypod photographs from Plate VII, DGS Report of Investigation No. 21, by T. E. Pickett, 1972.
1. Cliona cretacica - specimen from the Mount Laurel Formation<br>2. Hemiaster sp. - specimen from the Englishtown Formation<br>3. Gervilliopsis ensiformis - specimen from the Merchantville Formation<br>4, 5. Cucullaea neglecta - specimens from the Marshalltown Formation<br>6. Cucullaea vulgaris - specimen from the Merchantville Formation<br>7. Glycimeris mortoni - specimen from the Merchantville Formation<br>8. Inoceramus proximus - specimen from the Englishtown Formation<br>Plus More
1. Exogyra ponderosa - specimen from the Marshalltown Formation, also occurs in the Englishtown Formation and the Merchantville Formation<br>2. Exogyra ponderosa erraticostata - specimen from the Marshalltown Formation<br>3. Exogyra costata - specimen from the Mount Laurel Formation<br>4. Pyncnodonte mutabilis - specimen from the Marshalltown Formation<br>Plus More
1. Pholadomya occidentalis - specimen from the Merchantville Formation<br>2. Liopistha protexta - specimen from the Marshalltown Formation, also occurs in the Mount Laurel Formation, the Englishtown Formation, and the Merchantville Formation<br>3. Cymella bella - specimen from the Merchantville Formation<br> 4. Crassatella sp. - specimen from the Mount Laurel Formation, also occurs in the Marshalltown Formation, the Englishtown Formation, and the Merchantville Formation<br>Plus More
Clavagella armata - occurs in the Mount Laurel Formation<br>Liopistha protexta - occurs in the Mount Laurel Formation, the Englishtown Formation, and the Merchantville Formation<br>Postligata crenata - occurs in the Mount Laurel Formation and the Merchantville Formation<br>Cucullaea sp. - occurs in the Mount Laurel Formation, the Marshalltown Formation, and the Merchantville Formation<br>Plus More