Image: Busycon carica fossil knobbed whelk snail shell (Pleistocene; Lee Creek Mine, Aurora, North Carolina, USA) 5 (31826152322)

Description: Busycon carica (Gmelin, 1791) - fossil knobbed whelk shell (oblique apical view) from the Pleistocene of North Carolina, USA. (~9.7 cm across at its widest)

Of all the molluscs, the gastropods (snails) have made the most ecological adaptations. They can be found in almost all fundamental environments: marine, freshwater, terrestrial. Most gastropods live in the ocean, and have a single, asymmetrically coiled, external shell of calcium carbonate (CaCO3 - usually aragonite). The hard calcareous shell is the most easily fossilized part of the gastropod. The soft parts of a snail (the “slug” portion) include a well developed head having eyes, tentacles, and a mouth, and a well developed, strong, muscular foot used principally for locomotion. The shell is carried upright on the snail’s back, or is partially dragged behind. When threatened by a predator, many snails can retract their soft parts into the shell’s interior for protection.

Many fossil snails in the Paleozoic rock record are often not well preserved, or are preserved as internal molds. The original aragonite of many gastropod shells is not stable on geologic time scales, and often recrystallizes or dissolves completely away. Fossil snail shells in Mesozoic and Cenozoic rocks are usually better preserved.

Classification: Animalia, Mollusca, Gastropoda, Neogastropoda, Muricoidea, Melongenidae

Age: Pleistocene

Locality: Lee Creek Mine, Aurora, eastern North Carolina, USA
Author: James St. John
Usage Terms: Creative Commons Attribution-Share Alike 3.0
License: CC-BY-SA-3.0
License Link: http://creativecommons.org/licenses/by-sa/3.0/
Attribution Required?: Yes