Sunday, May 24, 2009

Turbinopsis shumardi or Pleuronotus decewi

Using the Fossils of Ohio (Bulletin 70: Ohio Division of Geological Survey; 1996) on page 154 in the chapter on Phyllum Mollusca, Class Gastropoda. I normally label the fossil shown in the pictures as Turbinopsis shumardi from the Jeffersonville Limestone.

I believe the Jeffersonville Limestone of Kentucky and Indiana corresponds to the Columbus Limestone in Ohio. The book describes "Pleuronotus decewi is a large, pseudoplanispirally coiled form that has sharp angulations forming the upper and lower margins of the whorls. It is also commonly preserved as an internal mold, which does not show the selenizone. The genus is restricted to the Devonian."

So maybe this snail could be the one described in the book? Ruler units are in centimeters.