This Specimen has been sold.
.3" Fossil Snail (Strobeus) - Illinois
This is a .3" fossil marine snail (Strobeus) from the Carbondale Formation near Essex. Illinois. It is preserved in an ironstone nodule and contains both the positive (convex) and the negative (concave) halves of the fossil.
Gastropods, which are more commonly referred to as snails, have been around since the Late Cambrian period. The class Gastropoda contains a vast total of named species, second only to the insects in overall number. There are 611 known families of gastropods, of which 202 families are extinct and appear only in the fossil record.