trilobite

Three lobes running head to tail (that is what the name means) and clear segmentation across the body.

Most Michigan finds are a fragment: a tail plate or a head shield rather than a whole animal. Rockport and Alpena County; genuinely scarce as beach float.

The genus is the honest answer. Michigan trilobites get sold and traded as Eldredgeops rana, but that is the Appalachian species, and the only Michigan record of true rana is from the Silica Formation down in the far southeast corner of the state, Monroe County. The Traverse Group animal up at Alpena is Eldredgeops norwoodensis, described by Stumm in 1953. A tail plate or a head shield cannot tell you which, so the chart stops at the genus.

One rule worth knowing before you go. Rockport is open and you may take up to 25 pounds a year, but that limit is for the whole state and for all material, and collecting vertebrate fossils on state land is not allowed at all. Rockport has the most diverse Devonian fish fauna in Michigan, so a bony plate is easy to pick up by accident. Leave the fish.