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.

Thursday, January 22, 2015

Possible Monoplacophoran fossil from the Ludlowville formation

Sometimes you make good finds not in the field but at home when you are sorting through your finds. The fossil below is such an example.When I picked it up I probably thought it was an inarticulate brachiopod but as I cleaned it up and looked more closely it seems to me that it might be something different. When you look at it in profile the very tip of the shell appears to point backwards rather than straight up. If this were an inarticulate brachiopod I would expect the tip to be straight or very muted. There also appears to be a hole in the tip of the shell which could indicate that the tip broke off or maybe it is supposed to be that way (anal opening?). My instincts are telling me this could be a Monoplacophoran which is a mollusk similar to a gastropod or snail but different enough to not be included with them. Still I am unsure as I can not find any information on Monoplacophorans being found within the Hamilton group.

I have found Monoplacophorans before but they came from the Ordovician of the Verulam formation.

Tuesday, January 20, 2015

Cypricardella tenuistriata pelecypod from the Panther Mountain formation

These next two specimens are Cypricardella tenuistriata pelecypod fossils. Both have the typical ovate shaped shell with a squared off posterior margin. The fact that the growth lines are very fine and not terribly distinct or raised eliminates the species C. bellistriata from contention.

Both fossils came from a roadside quarry on Cole Hill Rd. in Madison County, NY and come from the Panther Mountain formation (Devonian, Givetian stage) but the rock type is very similar to portions of the  Skaneateles formation (with which it is concurrent).

Specimen #1 - Right valve only

Specimen #2 - Left valve only

Sunday, January 18, 2015

Nucula bellistriata pelecypod from the Ludlowville Fm.

It's rare to find whole Peleycpod shells with no distortion so I was quite pleased to find this Nucula bellistriata fossil. It comes from the upper Ludlowville Formation (Devonian, Givetain stage) at Geer Rd. Quarry in Madison County, NY. Both valves are present and it even appears that one valve may still be preserved with shell material. It would be nice if the hinge line were better exposed but there is a stubborn piece of rock still clinging to that section of the fossil.

Right valve
Left valve
Left profile
Right profile

The Devonian rocks of Madison county are closer in composition to those of my local Devonian rock, the Mahantango formation. I've found this same genera in the Mahantango with both valves but it is preserved as a internal steinkern (cast) with no external features.

Friday, January 16, 2015

Brachiopods from the Utica Shale

I'll wrap up my series on fossils I found in the Utica Shale (Ordovician, Darriwillian stage) with this post concerning some Brachiopods that were among the specimens I brought home.

The first specimens are of Leptobolus insignia which are fairly common and scattred throughout the black shale. The appear to be a Lingulid type of brach which means they are inarticulate. Perhaps they lived in the mud or just on the surface of it.

Not much details in those pics because the shells are so small, only 1-3 mm in size. Here are some photos from my microscope or three different specimens.

The only other Brachiopod I found is this one that I think is a Paucicrura rogata.

It's much larger than the tiny inarticulate brachs. I'd say it got swept in by currents or a storm.

Wednesday, January 14, 2015

Possible coprolites from the Utica Shale

I found two interesting fossils in the Utica shale (Ordovician, Darriwillian stage) while looking for Trilobites this past fall. Both appear to be crushed and disarticulated remains of Triarthrus eatoni Trilobites. The difference between these specimens and others that are disarticulated is that these show no hint of organization and are broken into shapes not normally seen in molts. There are also small brachiopods scattered among the remains. I'm thinking these are corprolites from a large cephalopod or other predator who ate Triarthrus eatoni. The Brachiopods could be present because they colonized the coprolite as a hard substrate in an otherwise muddy sea floor.

Specimen #1

Specimen #2

Monday, January 12, 2015

Problematica fossil Sphenothallus from the Utica shale

One of the strangest fossils I found while collecting in the Utica shale (Ordovician, Darriwillian stage) has to be Sphenothallus. When I saw my first specimen in the field I thought it was nothing more than a deformed cephalopod but kept a sample for reference. Later on a friend of mine, Tim, who was collecting with me at the same locality that day and who also found a similar specimen, posted a picture to the Fossil Forum. Member "Fossilcrazy" (John) responded with an ID and showed some specimens he'd found in Canada in related rocks.

My specimen

Apparently Sphenothallus is a mystery fossil with no modern counterparts. Current theory has them related to either corals or worms (as noted by "Fossildude19" on the above thread).

This past week I've been sorting and cleaning some of my finds from the earlier collecting trip in the fall. I found two more examples of this enigmatic fossil. The first was on a large plate associated with Graptolites and small Brachiopods.

The second was found purely by accident as I was trimming down a large chunk of rock. A small piece split off and I saw the Sphenothallus fossil. I was able to recover both halves of the fossil but it's not as well preserved as the other two specimens.

Saturday, January 10, 2015

Cephalopods from the Utica Shale

Orthoconic cephalopods are also found in the Utica shale (Ordovician, Darriwillian stage) and can get somewhat large. The downside is that they are not preserved very well it can be difficult to definitively ID any specimen. These are some that I found this past fall on Nowadaga Creek. This first one is pyritized but not a great many details are retained.

Others are just impressions in the shale.

This specimen, however, does show evidence of sutures and chambers.

Various publications have ascribed the cephalopds found in the Utica shale variously to Endoceras,  and Geisonoceras. I posted pictures of a specimen I purchased back in 2011 here.