Big Spirifer Found In Barren Shale

[mikeymig]

A few years ago I went collecting at my favorite fossil site here in NY. When I got to the main outcrop I soon noticed that there was a large pile of shale the fell away from the cliff. At first glance there were no fossils to be seen until I started splitting the larger pieces of shale. The only fossils I found were well preserved Eldredgeops and nothing else. In fact I found eight complete trilobites in this pile and it took me all day to process everything. After that I tried to repeat my first run at this layer but always come up with very meager results (partial Eldredgeops). Occasionally I would find a pyritized cephalopod but I'm not even sure that I'm collecting in the same horizon I found the trilobites in.

Last week I went back to this locality after a gully washer cleaned the stream and exposed fresh shale. I was able to get at a large piece of shale from the trilobite layer. Splitting and splitting came up with nothing until I found a large pyrite cluster. Inside the pyrite were two large (3" x 2") spirifers that I thought were Mediospirifer. I told a friend about my find because it was the first time I have ever found brachiopods in this barren part of the Windom shale. He told me that they might be something else other then Mediospirifer like Spirifer marcyi. The Delthyrium is wider then Mediospirifer but I'm not a brachiopod expert so I would like to know what you think.

Mikey

[Auspex]

Three inches?! Wow!

What's up with the 'laminations' I've marked?

[Fossildude19]

Wow, that's a monster!

Nice one, for sure.

Now,.. to find the trilo layer again...

Regards,

[Shamalama]

Mikey, that is an odd one. Is the pedicle warped underneath or does it naturally go back that straight? Reminds me a little of a Mediospirifer "angustus" I found in the Hungry Hollow mbr. a few years ago.

-Dave

[GerryK]

Mikey

The difference between Mediospirifer and "Spirifer" marcyi is Mediospirifer has a smooth shell with growth lines and "Spirifer" marcyi has spiny pustules along growth lines. I can see the spiny pustules on the specimen on the right but can't see them on the left specimen. It needs to be cleaned or better photograph. It appears "Spirifer" marcyi has a close affinity with the genus Orthospirifer which is a common brachiopod in the Silica Shale of Ohio.

[mikeymig]

Auspex,

You often see these lines in the Inter-area of large spirifers like Mediospirifer and Spinocyrtia. Maybe this is where muscles attached?

mikey

[Auspex]

Auspex,

You often see these lines in the Inter-area of large spirifers like Mediospirifer and Spinocyrtia. Maybe this is where muscles attached?

mikey

Huh...I thought they might have been a geological artifact. Thanks!

[Shamalama]

Auspex,

You often see these lines in the Inter-area of large spirifers like Mediospirifer and Spinocyrtia. Maybe this is where muscles attached?

mikey

More likely growth lines, IMHO.

Gerry, good analysis. I've always wondered how to tell an Orthospirifer from a Mediospirifer.

[GerryK]

More likely growth lines, IMHO.

Gerry, good analysis. I've always wondered how to tell an Orthospirifer from a Mediospirifer.

Shamalama

I described the difference between Mediospirifer and "Spirifer" marcyi. Orthospirifer is different. It has a distinctive type of micro-ornament called capillae. They are fine lines that run from the back to the front of the shell and have nodes on them. "Spirifer" marcyi is different from Mediospirifer and Orthospirifer. It has not been assigned to any genus or described as a new genus. What ever the genus, I have recognized two other species that would be assigned to the same genus as "Spirifer" marcyi and they occur in the Ludlowville and Moscow Formations. The reason I stated that "Spirifer" marcyi appears to have a close affinity with the genus Orthospirifer is I found an older brachiopod in the Skaneateles Formation that has the capillae of Orthospirifer and the spiny pustules of "Spirifer" marcyi. It appears to be a transition between the two genera.

[Shamalama]

Gotcha Gerry. Thanks for clearing that up.