Crushed/warped Spirifer fossils from the Mahantango Formation

Below are some specimens of a Spirifer type brachiopod that I am tentatively calling Spinocyrtia granulosa.

Specimen #1 is crushed but retains details of the exterior of the shell.

Specimen #2 is a partial internal mold. Here you can see the striations where the pedicle muscle was attached.

Anterior

Brachical valve side that is also crushed and does not retain the shape of the shell very well.

Anterior

Left profile

Right profile

This is an isometric view of the posterior that shows a mold of the delthyrial cavity (the tongue like extension) where the pedicle muscle would have extended from.

Specimen #3 is another internal mold that has some distortion as well as crushing. The distortion is likely a reflection of the strain the fossil experienced as the rock around it was deformed during the building of the Appalachian mountains.

Pedicle valve

Anterior

Brachial valve

Posterior

Left profile

Right profile

After reviewing Plate 11 in "Stratigraphy and Paleontology of the Mahantango Formation in South-central Pennsylvania" (Ellison, 1965), I'm convinced that what I found can be called Spinocyrtia granulosa.

All three specimens were collected from a site near Liverpool, PA from the Mahantango Formation (Devonian, Givetian stage).

Palaeoneilo emarginata pelecypod from the Mahantango formation

Just a simple one picture post today. It's a Palaeoneilo emarginata pelecypod mold that I found in the Mahantango Formation (Devonian, Givetian stage) near Liverpool, PA.

There are some other shells on the same piece such as the Chonetes sp. just above the P. emarginata and possibly an Atyrpa sp. below it.

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.

Modiomorpha pelecypod from the Mahantango

I have posted some specimens of Modiomorpha from the Mahantango formation before but this specimen is different in that there is some shell material preserved. It's not the original shell but more likely a replacement by Calcite.

The shell cast is not complete but this is still an uncommon occurrence from the Mahantango formation (Devonian, Givetian stage) since I often find the weathered, leached molds of pelecypods. This specimen came from near Liverpool, PA.

Some gastropods from the Mahantango formation

I'm going through some boxes of findings from the Mahantango formation (Devonian, Givetian stage) and came across some decent gastropod fossils that I found at Liverpool, PA.

This is a Cyclonema mold in matrix with a little bit of the exterior shell cast intact. There is also a Nucula varicosa pelecypod just above and to the right of it.

Then there is this mold from the internal chamber of a gastropod. It's tightly coiled and the whorls stack internally rather than rise up like most snails fossils I've seen. It seems to be a fairly wide living chamber and the width of the whorls increases rapidly unlike the Goniatites of the era.

Here you can see the groove where the whorl pressed against the previous shell area.

Maybe this is a Straparoullus or Tropidodiscus? With the small amount of info that I can find online I'm leaning towards Tropidodiscus.