Plaesiomys brachiopod from the Verulam fm

Plaesiomys is easily recognized while collecting in the Verulam formation. It has a rectangular outline and strong radiating ribs on the surface of the pedicle and brachial valves. It also has a triangular shaped interarea in the posterior.

Specimen 1 pedicle valve

Specimen 1 anterior

Specimen 1 brachial valve

Specimen 1 posterior

Specimen 1 profile

Specimen 2 pedicle valve

Specimen 2 anterior

Specimen 2 brachial

Specimen 2 posterior

Specimen 2 profile

Both of the above specimens were collected from the Verulam formation which is middle Ordovician in age (Katian/Mohawkian stage) near Brechin, Ontario.