Sunday, 18 August 2019
There are lovely brachiopods, including the spiriferids Striipirifer and Eospirifer, the strophomenids Leptaena, Coolinia and Amphistrophia. We also see the orthids represented by Mendacella (formerly Dalejina) and Resserella.
They shales also house a stunning assortment of our echinoderm friends with their radial symmetry. We see cystoids, crinoids, asterozoans and edrioasteroids. The diversity of the crinoids is especially spectacular. We see the camerates Macrostylocrinus, Dimerocrinites, Saccocrinus and Eucalyptocrinites. Cladids are represented by the elegant and long-stemmed Dendrocrinus, with his lengthy anal sac and branched, non-pinnulate arms. Disparids occur as the wee Homocrinus, recumbent calceocrinids (Calceocrinus) and the coiled, Crinobrachiatus with his coiled bilateral symmetry.
We also see the flexible crinoids represented by Asaphocrinus, Icthyocrinus and Lecanocrinus. Gracing many of the beds is the rhombiferan cystoid Caryocrinites scattered in bits and pieces and on rarer occasions fully intact, sometimes with rooted specimens associated with bryozoan thickets. The edrioasteroid Hemicystites occurs in select layers referred to as the Homocrinus Beds. These beds record a history from when the area that is now New York State was located south of the equator and covered by an ancient shallow sea.
The Lewiston Member of the Rochester Shale were first studied by James Hall in the 1850-60's. Many great paleontologists have contributed to our understanding of their place in geologic and paleontological history, including Eugene Ringueberg's work from 1884-88; Frank Springer's studies from 1914-22 and Carlton E. Brett (along with his students, Denis Tetreault, James Eckert and Wendy Taylor) in the 1970-90's.
While the site became famous back in the 1820s, it is because of these latter paleontologists that I came to know about the site and appreciate the full breadth of fauna. Collection of Felix Collantes. If you are interested in the diversity of fauna from this area, I highly recommend the 1999 publication by Taylor and Brett referenced below. It's a definitive work.
Reference: Taylor and Brett 1999: Middle Silurian Rochester Shale of Western New York, USA, and Southern Ontario, Canada