Glycymeris Clam Internal Mold

Taxonomy

Bittersweet Clam

Kingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
Order: Arcida
Family: Glycymerididae
Genus: Gycymeris
Species: Gycymeris mortoni
Author Citation (Conrad, 1869)

Geological Time Scale

Eon: Phanerozoic
Era: Mesozoic
Period: Cretaceous
Sub Period: None
Epoch: Late

Stratigraphy

Monmouth Group
Mount Laurel Formation

Provenance

Collector: Heather Siple
Date Collected: 01/21/2021
Acquired by: Field Collection

Dimensions

Thickness: 4 mm
Diameter: 10 mm

Location

Reedy Point Spoils, North Side
New Castle
Delaware
United States

• bivalve
• c and d canal
• clam
• cretaceous
• delaware
• fossil
• glycymeris
• mount laurel formation
• navesink formation

Comments

Glycymeris clams have ridges along the inside edge of the valves that extend past the cardinal area. Internal molds tend to include these teeth, making them very distinctive. 

 

As of the time this was posted, this was the only member of the genus listed in the Paleobio Database for the Cretaceous period and it is only listed as being found in NJ. However, Stuart Weller (1907) and Horace G Richards (1958) not only include them in the C and D Canal zone, but identify three different species for the region. This one is the most common and the only one THEY found outside of NJ.

 

This is most likely from the Mount Laurel formation. It was found among the Mount Laurel index fossils. However, Navesink Formation fossils are also found in pockets in this spoils area, so the possibility that this came from the Navesink and got mixed up with the Mount Laurel material from constant human activity cannot be ruled out.