Sunday, February 1, 2015

Longispina mucronata brachiopod from the Ludlowville formation

I picked up this slab of chonetid type brachiopods while visiting a small quarry off Geer Rd. in Madison County, NY. The rock found there is a portion of the Upper Ludlowville formation (Devonian, Givetian stage) which has these zones of shell "pavement". Most of the shells I can't really identify beyond "Chonetid type" because to distinguish between the genra you'd need to see if they had spines growing off the hinge line. As the spines are delicate they often get broken off before the shell gets buried.

I was happy enough with the slab as is but, as I looked at some of the individual shells more closely, I found one that appeared to have spines preserved. I always do a happy dance when this happens but especially so in this case because I was able to determine that the species is Longispina mucronata.

The slab

A close up view of the shell. You can see the horizontal spine poking out of the left side of the hinge line.

Not satisfied with just a close view from my camera I took the piece up to my microscope and took a picture there. Here is a much closer view of the spine and I was pleased to see two more parallel to it coming from points farther in along the hinge line.

I've annotated this version of the above picture with what I interpret are the spines in white and the shell outline in red.

I have found a shell that I've called Longispina before in the Mahantango Formation (Devonian, Givetian stage) of PA, but this specimen looks a little different.

I also have a specimen that is labelled as Longispina lissohybus from the Silica Shale (Devonian, Givetian stage) of OH, but there are no spines preserved on that specimen.

Friday, January 30, 2015

Paracyclas rugosa pelecypod from the Panther Mountain formation

I broke this fossil while trying to hand trim some of the excess rock from around it but it glued together pretty well. It's a Paracyclas rugosa from the Panther Mountain formation (Devonian, Givetian) at Cole Hill in Madison County, NY.  Paracyclas rugosa is a small pelecypod that is nearly circular in outline and sometimes can be confused with a terebratulid brachiopod.

I've posted several examples of this genera before from the Silica Shale, Mahantango Formation, Arkona Formation, Jeffersonville Formation and Lime Creek Formation.

Wednesday, January 28, 2015

Cornellites fasiculata pelecypod with a bryozoan from the Panther Mountain formation

This rock is full of fossils but the one that made me keep it was the impression of a Cornellites fasiculata pelecypod. The detail of the mold is really nice but there is a little "window" in the mold that shows evidence of an encrusting bryozoan that had colonized the shell.

This is the whole rock with the impression near the bottom. The rounded object just above it (and casting the shadow) is the pygidium of a Dipleura dekayi trilobite.

When you look into the shadowed area you can see the "window

Here is a closer view and the cool thing is that you can see the clam shell, the base of the bryozoan and what looks like a worm tube that may have been on the shell before the bryozoan. The undulating shape of the bryozoan makes me think it could be a Leptotrypella species.

This fossil came from the Panther Mountain formation (Devonian, Givetian stage) at Cole Hill Rd., Madison County, NY

Monday, January 26, 2015

Bembexia sulcomarginata gastropod from the Panther Mountain formation

This is a pretty decent gastropod specimen from the Panther Mountain formation (Devonian, Givetian stage) at Cole Hill, NY. It's a Bembexia sulcomarginata and retains a little of the original shell texture. The curved lines that are perpendicular to the shell spiral are key to identifying this species. Despite the presence of the shell texture, this is still considered a steinkern (or cast) of the specimen. It has a nice three dimensional shape and is missing just the tip of the spiral.

I've also found this genus in the Needmore Shale of Pennsylvania.

Saturday, January 24, 2015

Lyriopecten orbiculatus pelecypod from the Panther Mountain formation

The pectin like pelecypods of the Devonian can be beautiful with their regular concentric ornamentation highlighted by radial ribs and "wings" along the hinge line. The fossil below is one that I do not recognize but I think I found a name for it while perusing the "Field Guide to the Devonian Fossils of New York" by Karl A. Wilson, 2014, Paleontological Research Institution.

On page 148-149 is a pelecypod called Lyriopecten orbiculatus whose description is
 "Roughly circular shell with short hinge line, very small to absent anterior ear, and small posterior wing. Left valve convex, right valve slightly convex to concave. Surface marked by strong rays crossed by sharp concentric growth lines."
The shell I found is a right valve, although it's seen in reverse as it's a mold of the original, slightly convex with strong rays and concentric growth lines. It came from the Panther Mountain formation (Devonian, Givetian stage) in a quarry along Cole Hill Rd. in Madison County, NY.