English: Dictyoclostus sp. - brachiopod in sandstone from the Mississippian of Ohio, USA.

The Byer Sandstone is one of four stratigraphic units in the Mississippian-aged, siliciclastics-dominated Logan Formation of eastern Ohio. Ascending from the base, they are the Berne Conglomerate Member, the Byer Sandstone Member, the Allensville Member, and the Vinton Member. The Byer is dominated by quartzose sandstones.

The fossil is a mold of a Dictyoclostus productid brachiopod. The original calcareous shell is gone. Brachiopods are sessile, benthic, filter-feeding, marine invertebrates. They first appear in Cambrian rocks and were abundant in Earth's oceans throughout the Paleozoic. They were also common in Mesozoic oceans, but are scarce in modern oceanic biotas. Brachiopods have two shells, called valves, that are usually calcareous (made of calcite - CaCO3 - calcium carbonate). Each shell of a brachiopod is bilaterally symmetrical, unlike each shell of a bivalve (clam).

Classification: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Strophomenata, Strophomenida, Productidae

Stratigraphy: Byer Sandstone Member, basal Logan Formation, Waverly Group, Osagean Stage, upper Lower Mississippian

Locality: crack surface, stream pebble from gravel bar along unnamed south-flowing tributary of Clear Fork, just north of the Chatham Road bridge, western side of the town of Chatham, northwestern Newton Township, northern Licking County, east-central Ohio, USA