English: Productid brachiopod in fossiliferous limestone in the Pennsylvanian of Ohio, USA.

The Lower Mercer Limestone is a Middle Pennsylvanian-aged, laterally persistent, marine fossiliferous limestone unit in the Pottsville Group of eastern Ohio, USA. It is richly fossiliferous, principally dominated by brachiopods and crinoid stems. The fossil shown above is a productid brachiopod. Brachiopods are sessile, benthic, filter-feeding, marine invertebrates. They first appear in the Cambrian and are still alive in modern oceans. They all have two shells - most have shells of calcite (CaCO3 - calcium carbonate). Brachiopods dominated Paleozoic shallow seafloors. They were also fairly common in Mesozoic oceans. They are scarce in modern seas.

Eleven different productid brachiopods have been reported from the Lower Mercer Limestone: Kozlowskia haydenensis, Desmoinesia muricatinta muricatina, Desmoinesia muricatina missouriensis, Echinaria semipunctata knighti, Antiquatonia costellata, Antiquatonia portlockiana quadratia, Juresania nebrascensis inflatia, Linoproductus planiventralis, Linoproductus echinatus, Cancrinella bonnensis, and Krotovia paucispina.

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

Locality: large talus block along the northern bank of Symmes Creek, just upstream of the North Fork/North Branch confluence & just upstream of the Mollies Rock Road bridge over Symmes Creek, Madison Township, northern Muskingum County, eastern Ohio, USA

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Some info. from:

Sturgeon & Hoare (1968) - Pennsylvanian brachiopods of Ohio. Ohio Division of Geological Survey Bulletin 63. 95 pp. 22 pls.