|Calymene blumenbachii, Theresa Paul Spink Dunn|
Calymene blumenbachii, sometimes erroneously spelled blumenbachi, are found in the limestone quarries of the Wren's Nest in Dudley, England. This locality name was charmingly highjacked by an 18th-century quarryman birth the nickname the Dudley Bug — both a symbol of the town and a key feature on the Dudley County Borough Council Coat-of-Arms. Calymene blumenbachii is commonly found in Silurian rocks — 422.5-427.5 million years ago — that formed near shallow water, low energy reefs.
This particular species of Calymene — a fairly common genus in the Ordovician-Silurian — is unique to the Wenlock series in England and comes from the Wenlock Limestone Formation in Much Wenlock and the Wren's Nest in Dudley. These sites seem to yield trilobites more readily than any other areas on the Wenlock Edge. The rock here is dark grey and quite fossiliferous. Just a few miles away in Church Stretton and along other parts of the Edge, it is yellowish or whitish — an indication that there were local changes in the environment in which the rock was deposited. The Wenlock Edge quarry is closed to further collecting but may reopen for future research projects.