Platyostoma gastropod and Stereolasma coral from the Mahantago

As I'm parsing through my findings and cataloging the pieces I want to keep, two new species will joining my collection of fossils from the Mahantango Formation of Pennsylvania.

The first is this internal mold from the gastropod Platyostoma (Nanticonema) lineata. It is somewhat intact and free of any distortion unlike some fossils found in nearby exposures in the same pit.

...and this partial rugose coral that I think is Stereolasma rectum. All that I found is this little stump with septa converging on the interior

and what may be septal grooves on the exterior. I wish I could have found the rest of this guy as rugose corals are somewhat rare in the Mahantango.

Both of these specimens came from an exposure of the Mahantango Formation (Devonian, Givetian stage) near Liverpool, PA.