Invertebrate Fossils of NJ
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 Most gastropods have a single, usually spirally coiled shell into which the body can be withdrawn, but the shell is lost or reduced in some groups.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.
Examples of original aragonite shell material (5 mm)
A few additional types of preservation.
The picture doesn't do the colors on this specimen
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