Fossil Brachiopods. Description: Brachiopods are marine animals that secrete a shell consisting of two parts called valves. Their fossils are common in the Pennsylvanian and Permian limestones of eastern Kansas.. Brachiopods have an extensive fossil record, first appearing in rocks dating back to the early part of the Cambrian Period, about 525 million years ago.
The pedicle opening (delthyrium), located between the valves, is either uncovered, as in Obolella, or closed off by convex plates (pseudodeltidium). The mantle canal system lacks bifurcations (baculate type) in both valves (see Fig. a & b).