Moscow Formation mystery fossil. Middle Devonian

[Bennett-s]

Fossil is from Western New York. This round fossil only had the white-colored oval on the edge exposed when I found it. Using a dremel, I was able to expose a lot of it. At first the pieces chipped right off, but the further I got into the matrix, the stickier and harder it got. I gave up on it at the point seen in the pictures because I wanted to have an idea of what shape the rest of it is before I continue.
 

The circular fossil is about the size of a quarter, maybe 20mm to 25mm across. My guesses of identification range from the inner-cast of a gastropod shell to a goniatite. As you can see, it is smooth.

The last two images are of the other side of the rock with what appears to be two cross sections of unknown fossils. I had hoped the were nautiloids but I could not get anywhere with removing the matrix around it and so I do not know.

I am very new to fossil preparation which is why the work probably looks shoddy.

 

[Fossildude19]

The round one looks like a possible gastropod - maybe Naticonema lineata.

 

Not sure on the other one, as the preservation is so poor. 

 

 

@Jeffrey P