Platyostoma niagarensis Snail Fossil

 

On a recent trip to Napoleon, Indiana USA, I found this gastropod fossil which might be a Platyostoma niagarensis (Hall, 1852). It dates to the Silurian Period  (Telychian to Sheinwoodian stage) in age.

According to Dr. James Thomka, professor at SUNY Plattsburgh, it is "from the mudstone lithofacies of the Massie Formation (long known as the "upper Osgood shale"), which is renowned for its 'cystoid' fauna."