The limestone contains marine fossils including crinoids, brachiopods, gastropods, horn corals, and bryozoans. The locality is also rich in crinoids, gastropods, bivalves, brachiopods and bryozoans. Invertebrates like brachiopods, gastropods, and molluscs were severely affected. Marine fossils found in Port Talbot region include species of bivalves, gastropods and brachiopods. Consequently, sea creatures such as trilobites, brachiopods, and graptolites became extinct. These include corals, stromatoporoids, algae, brachiopods, gastropods and straight nautiloids. Fossils found in the sedimentary rocks in the park include algae, brachiopods and trilobites. Their diet consisted of marine bivalves, brachiopods, and other invertebrates. Trilobites, the mollusc-like brachiopods, and the great coral reefs were still common. Trilobites, the mollusk-like brachiopods and the great coral reefs, were still common. Examples include the shells of invertebrates, such as molluscs and brachiopods. Calcium carbonates constitute the shells of molluscs, brachiopods, and some tube-building polychaete worms. Trilobites and brachiopods in particular were rich and diverse. These include sponges, ammonites, radiolarians, brachiopods, and the belemnite "Aulacoceras". The Lophotrochozoa includes the molluscs, annelids, brachiopods, nemerteans, bryozoa and entoprocts.