Plectatrypa from Lockport, NY

When exploring a new rock formation and picking up fossils you often find some that are somewhat abundant but you have no idea what they are. It then follows that you spend time asking others for info or searching through books trying to find a match. The specimen below, from the Irondequoit limestone Rochester Shale near Lockport NY, is just such a troublesome fossil. While it has required some research to find information about the fossils that are found within the Irondequoit limestone Rochester Shale are well documented. This does not always cover every instance though and it took until I read through a book called "Paleocommunities—A Case Study from the Silurian and Lower Devonian", A.J. Boucot and J.D. Lawson, editors, 1999, Cambridge University Press, Cambridge. It had a chapter that described the brachiopod community that can be found within the Irondequoit limestone/Rochester Shale. In the list it has Plectatrypa sp. as a common member but I was having a hard time finding any pictures of specimens to compare mine to. Then I stumbled across this page (plates Plates XVIII & XXII) which is part of the "Paleontology of Kentucky" by Willard Rouse Jillson that was published in 1931. The examples illustrated looked similar to what I had found and were from the Silurian (as is the Irondequoit limestone Rochester Shale which is falls within the Wenlock series, Shienwoodian stage) I think I have a match.

Which brings us to the specimen that I found and am naming Plectatrypa sp.

Pedicle valve

Anterior

Brachial valve

Posterior

Profile

I think this specimen is also a Plectatrypa.
Pedicle valve

Anterior

Brachial valve

Posterior

Profile

Hopefully the research I have done resulted in the correct name being assigned to the fossil and will be helpful for others searching to examples.