File:Anthracospirifer fossil brachiopod in fossiliferous limestone (Boggs Member, Pottsville Group, Pennsylvanian; Rt. 93 roadcut north of Mt. Pleasant, Hocking County, Ohio, USA) 2.jpg

English: Anthracospirifer fossil brachiopod in fossiliferous limestone from the Pennsylvanian of Ohio, USA.

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).

The brachiopod shown above is a spiriferid from the Pennsylvanian-aged Boggs Member in southeastern Ohio. The Boggs Member is a relatively thin stratigraphic interval. It typically consists of marine fossiliferous limestones, dominated by brachiopods and crinoid ossicles. Significant lateral lithologic variation is present - Boggs lithologies range from fossiliferous limestone to intraclastic limestone to ferruginous chert to "flint" to dolostone. In places, it has a relatively high component of disseminated pyrite. In other places, it is relatively rich in black manganese oxide(s).

Classification: Animalia, Brachiopoda, Articulata (a.k.a. Rhynchonelliformea), Spiriferida, Spiriferidae

Stratigraphy: upper Boggs Member, middle Pottsville Group, lower Atokan Stage, lower Middle Pennsylvanian

Locality: Mt. Pleasant North Outcrop - near the top of a roadcut on the eastern side of Rt. 93, just north of the town of Mt. Pleasant, southern Washington Township, southern Hocking County, southeastern Ohio, USA (39° 23' 51.35" North latitude, 82° 27' 14.15" West longitude)