The two large shells above are pelecypods (clams). The photo on the left above may be the mold of the shell, where the shell itself has eroded away. As you hunt clams here, look for the assymmetrical shell. A line drawn down the middle of a single valve does not divide it into equal halves as it would a brachiopod shell. Clams were scarcer in the Paleozoic than they are today, but they were common in some localities. Here they are inconspicuous except for those above. Clams and oysters are in the Phylum Mollusca, as are snails, scaphopods, chitons, squids and octopi.