Modern examples of gastropods are snails and conchs. In the chert gravels, gastropod fossils consist usually of the inside casts of their shells. Pelecypods - Pelecypods are a mollusk characterized by a shell that has two halves that are typically mirror images of each other. Although less common in the Paleozoic shallow seas, they are currently abundant in modern saltwater and freshwater environments. Oysters and clam are modern examples of pelecypods.
Trilobites are an important group of extinct marine arthropods characterized by a segmented body.
A central ridge divides the body into three lobes for its entire length. A typical trilobite processes a distinct head, mid-section, and tail. Although and abundant fossil in most sedimentary of the Paleozoic Era, they are rarely found within the chert gravels of Louisiana. Also, Tertiary age petrified wood is present in the gravels of the Citronelle Formation. Generally, it occurs as pebbles scattered throughout the chert gravel.