Saturday, February 11, 2012

Lepidocyclus brachiopod from the Verulam fm.

In the Verulam formation Lepidocyclus is a somewhat uncommon brachiopod. It has a rounded shell that sometimes approaches spherical in shape. That and the growth lines that often decorate the shell distinguish it from Rhyncotrema. After a discussion with the author of "South-Central Ontario Fossils", Bill Hessin, I have come to the realization that these shells are Rhyncotrema increbescens and not Lepidocyclus.

This is a loose brachial valve embedded in the matrix.

It displays imbricating strong growth lines very well. One of the keys, that I've now learned, is that if the imbricating growth lines only cover the front 1/3rd of the shell then the genera is Ryhncotrema.

Here is a loose specimen
Pedicle valve


Brachial valve



Both specimens shown above were collected from the Verulam formation near Brechin, Ontario. The Verulam formation is Ordovician (Katian/Mohawkian) in age.

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