A. Fossil coiled in a single plane 1. Shell divided by internal transverse partitions or sutures Cephalopod 2. Shell without internal partitions or sutures Gastropod 3. Shell small, spindle-shaped; resembles wheat grain. Pennsylvanian and Permian Foraminifera fusulinid B. Fossil not coiled 1. Shells or valves similar to clams a. Plane of symmetry parallel to hinge; equivalved Pelecypod b. Plane of symmetry almost at right angles to hinge; strongly ribbed; “Scallop-like” with “ears”, inequivalved Pelecypod c. Plane of symmetry at right angles to hinge-line; without “ears”, not “Scallop-like”; commonly with opening in beak, inequivalved Brachiopod 2. Fossil tapering, cylindrical or cone-shaped a. Cone-shaped, internal longitudinal partitions or septa Coral b. Tapered, internal transverse partitions Cephalopod c. Shell without internal septa or partitions (1.) Shell large heavy, longitudinal ribs. Cretaceous only Rudistid (2.) Shell small, tusk-shaped, open at both ends, rare in Paleozoic and Mesozoic rocks Scaphopod 3. Fossil heart-shaped, domed or flattened; star pattern on top Echinoid 4. Fossil segmented a. Divided into 3 lobes, may be curled up. Paleozoic only Trilobite b. Flattened or elongate, resembles shrimp Crustacean [Illustration: Plate 8 Fossil Identification Chart III NO APPARENT SYMMETRY]