InvertebratesSite MapHomeTime Scale

 

Invertebrate Fossils of NJ

Gastropods
 

Class:  Gastropoda (Cuvier, 1795)
 

Gastropods are one of the most diverse groups of animals and include such common forms as snails, slugs, and whelks. Most gastropods have a single, usually spirally coiled shell into which the body can be withdrawn, but the shell is lost or reduced in some groups. In most New Jersey collecting locations fossil gastropods are only found as internal molds or casts known as steinkerns. This is the result of acidic ground water dissolving the original shell material ((see the aragonite dissolution discussion). A few locations in New Jersey do produce original shell material and I've included examples of both types of preservation.

(Richards et al, 1962)   lists over 130 species of gastropod from New Jersey and this number is low.


 

Typical Cretaceous finds.Most of the gastropods found in NJ are internal molds or casts which do not hold up well to stream wear.
I find trying to identify steinkerns difficult and normally don't even try.

Monmouth County, NJ


 

Pyropis trochiformis is a common Cretaceous find.
 The
low-spiral on this snail is distinctive making identification  possible.

 

 


A few areas in southern New Jersey do produce original shell material. Most of these shells are
either small or very fragile and require a good deal of patience to collect and prep.

Hexagonal platelets of aragonite give mother of pearl it's iridescence.
 


 

Examples of original aragonite shell material (5 mm)
Woodbury Formation
Cretaceous
 


A few additional types of preservation.

 

Pyrite

Pyrite shows up in most of New Jersey, it's just not very common.
 


 

The picture doesn't do the colors on this specimen justice.
A pyrite gastropod with bornite crystals. I've only seen this from one location and only a couple were found.

Woodbury Formation
Cretaceous


References and Notes::

Richards, H. G., 1958. The Cretaceous fossils of New Jersey. (Part 1). New Jersey Dept. of Conservation and Economic Development. New Jersey Geology Survey Bulletin, vol. 61, 266 p., 46 pls.

Richards, H. G., 1962. The Cretaceous fossils of New Jersey (Part 2). New Jersey Dept. of Conservation and Economic Development. New Jersey Geology Survey Bulletin, vol. 61, 237 p.
 
Wade, B., 1926. The fauna of the Ripley Formation on Coon Creek, Tennessee. U.S. Geological Survey, Professional Paper no. 137, 272 p., 72 pl.

 

Home Site Map Invertebrates