Thursday, April 30, 2020

Goniophora hamiltonensis pelecypod from the Moscow Formation

The large shell of Goniophora hamiltonensis is easy to recognize but the trapezoid shape with a rounded anterior end and an angular posteior end with two straight edges that almost meet at a 90 degree angle. This specimen is somewhat 3D in shape so the ridge, that angles down from the umbo to the margin where the straight edges meet, is very prominent.  Concentric growth lines finish off the decoration on the shell exterior.

Looking down the ridge

This specimen has a few interesting features that I interpret as worm tubes and an inarticulate brachiopod that lived on the interior of the shell as it lay on the seafloor. My interpretation of this is based on the presence of linear bumps that have the concentric growth lines passing over them. the roundish blob that is near the ridge of the shell look like the cemented brachial valve of a Petrocrania sp. type inarticulate brachiopod.  All of these interpretation make me think that this fossil is a cast of the original shell.


This specimen was found at a borrow pit on Deep Springs Road in Madison County, NY which exposes the Windom shale member of the Moscow formation (middle Devonian in age, Givetian stage.)

Tuesday, April 28, 2020

Orbiculoidea truncata brachiopod from the Moscow formation

Some inarticulate brachiopods made their shells from a phosphatic mineral composition and so their shells are often colored black when preserved. Below is a good example of an Orbiculoidea truncata that I found in the Windom shale. The shell is small, round, and is conical in shape with an offset beak. Concentric growth lines are present though some parts of the shell are missing.  This is the pedicle valve which was also the "top" of the brachiopod as the brachial valve would have been cemented to a hard substrate.








This specimen was found at a borrow pit on Deep Springs Road in Madison County, NY which exposes the Windom shale member of the Moscow formation (middle Devonian in age, Givetian stage.)

Sunday, April 26, 2020

Favosites hamiltoniae coral from the Moscow formation

It is unusual to find coral fossils at the Deep Springs Road quarry as the rock is a limy siltstone. One would not think a coral like Favosites hamiltoniae would like the muddier water. Perhaps it was washed in during a storm or records a less muddy interval that allowed the coral to thrive. In either case this is a cool specimen for the rarity of it being found at this location.  It appears to be a part of a larger, branching body and I only found a part of it. There is still quite a bit or rock covering the specimen and filling in the corallites.
 




This is a shot from the base of the specimen (on the right hand side of all the above pictures). Too much rock to see much detail but perhaps I will slab off the end and polish it to show the structure.

This specimen was found at a borrow pit on Deep Springs Road in Madison County, NY which exposes the Windom shale member of the Moscow formation (middle Devonian in age, Givetian stage.)

Friday, April 24, 2020

Grammatodon hamiltoniae pelecypod from the Moscow formation

This small fossil pelecypod right valve has been an interesting one to learn about. It is oval in shape with a somewhat flat to angular anterior and a rounded posterior. On the surface of the shell there are regular concentric growth lines and also some radiating striae. The striae (elevated portions of the shell that look like rays extending from a common point) are odd in that they break at the growth lines, pause for a short distance and then restart, becoming thicker and more prominent as they near the next growth line.

The specimen - An isolated right valve. Anterior is to the left, Posterior to the right, The beak is about 1/4 of the way along the hinge line from the Anterior margin. (Don't forget to click on the pictures to get a larger view)


The "broken" striae is the part that threw me off because the shell bears a resemblance to Phthonia sectifrons and Pholadella radiata, both of which have strong concentric growth lines and radiating striae, but they just didn't match close enough. I wrote to Professor Karl Wilson of the SUNY at Binghamton and he suggested Grammatodon hamiltoniae.

A Google search for the name Grammatodon led me to a document I was familiar with that updated the names used in the well known (in the Devonian paleontology circles at least) book "Geology and Paleontology of 18 Mile Creek" by Amadeus Grabau. In the document it listed Gramatodon hamiltoniae as replacing Macrodon hamiltoniae. With that information I was able to look up the original description in the "Paleontology of New York" Vol 5, Part II, pg. 349 by James Hall:

MACRODON, LYCETT. 1845.
MACRODON HAMILTONIAE.
PLATE LI, FIGS. 1-7,9, 10.

Shell of medium size or larger, sub-elliptical or sub-ovate, wider behind; length about twice the height; basal margin broadly curving, sometimes nearly straight in the anterior portion. Posterior extremity broadly rounded, sometimes sub-truncate in the upper half. Cardinal line essentially straight, obtusely sub-angular at both extremities. Anterior end abruptly rounded or sub-truncate.

Valves convex in the posterior portion and gibbous in the anterior and umbonal portions.

Beaks sub-anterior, prominent, rising above the hinge-line. Umbonal region regularly gibbous.

Surface marked by regular, sub-equidistant, lamellose, concentric lines and by fine radiating strire, which are usually interrupted at the edges of the lamellae and become thickened at their lower extension. The radii are stronger on the posterior part of the shell.

The hinge structure has the usual characteristics of the genus.

The description matches much more closely to the shell I found. I am not sure when Macrodon was replaced with Grammatodon, but the latter was named by Meek and Hayden in 1860.

I do so love when a mystery gets solved.

This specimen was found at a borrow pit on Deep Springs Road in Madison County, NY which exposes the Windom shale member of the Moscow formation (middle Devonian in age, Givetian stage.)

Wednesday, April 22, 2020

Fossil plant branch from the Moscow formation

From time to time one can find evidence of the growing forests that were spreading during the middle Devonian. Below is an example of what I believe to be a branch from an ancient tree that was washed out to sea and buried in the mud. There are no real diagnostic features that can tell me what it used to belong to but the fossils' linear growth and a 90 degree turn on part of it rules out that it could be a trace fossil from a burrowing animal. If this were a trace fossil the 90 degree turn would blend in better with the rest of the fossil and not look like a separate branching structure.  Besides, most natural burrows or trace fossils do not make 90 degree bends parallel to the rest of the trace.  It could have belonged to one of the fossil trees known from this era: Cladoxylopsids or Archaeopteris.

Check out the article about the oldest known fossil forest being found in New York near Cairo which is south and east of the locality where I found this fossil.

Specimen #1



Specimen #2







I've also found evidence of fossil branches washed out to sea in the Mahantango formation of Pennsylvania which is contemporaneous to the Moscow formation.

These specimens were found at a borrow pit on Deep Springs Road in Madison County, NY which exposes the Windom shale member of the Moscow formation (middle Devonian in age, Givetian stage.)

Monday, April 20, 2020

Prothyris lanceolata pelecypod from the Moscow formation

I need to trim this rock down a bit more but the highlight is the presence of the pelecypod Prothyris lanceolata. It is a small, very narrow shell longer than wide. The anterior end of this right valve is cut off due to where the rock broke but the posterior is intact and shows the sharp oblique curve typical of the species. I found this in the Windom shale of New York.

Specimen #1 - Right valve



Specimen #2 - Left valve




Thess specimens were found at a borrow pit on Deep Springs Road in Madison County, NY which exposes the Windom shale member of the Moscow formation (middle Devonian in age, Givetian stage.)

Saturday, April 18, 2020

Nuculites oblongatus pelecypod from the Moscow formation

This appears to be my first post about a fairly common Pelecypod from the middle Devonian: Nuculites oblongatus. It's an small, oval shaped shell with fine concentric growth lines. The specimen below is an internal cast of the left valve. You can tell by the faint vertical line just to the right of the beak of the shell which is a muscle attachment point. This one comes from the Windom shale or New York.



This specimen was found at a borrow pit on Deep Springs Road in Madison County, NY which exposes the Windom shale member of the Moscow formation (middle Devonian in age, Givetian stage.)

Thursday, April 16, 2020

Bactrites aciculum cephalopod from the Moscow formation

There are lots of orthoconic cephalopod fossils from the Paleozoic that often get lumped into the "Orthoceras", or in the Devonian period "Michelinoceras", name because of a lack of defining features.  Sometimes though you do find a smaller, thinner variation on the theme that can be narrowed down to the Bactrites genus. Below are two examples of the species Bactrites aciculum from the Windom shale in New York. They are long and thin with a max width of 1cm. Often the shells are crushed laterally during the compression of the mud they are encased in which leaves them with a line or ridge running the length of the shell.

Specimen #1 - This is a nearly complete specimen with only part of the living chamber extening off the rock and the narrowest part of the start of the shell still hidden by rock. Note that there appears to be chamber lines perpendicular to the main shell axis present on this specimen.



Specimen #2 is smaller and less complete but you can also just make out what appear to be chamber segments.


These specimens were found at a borrow pit on Deep Springs Road in Madison County, NY which exposes the Windom shale member of the Moscow formation (middle Devonian in age, Givetian stage.)

Tuesday, April 14, 2020

Fossilized burrow traces from the Moscow formation


I don't usually collect random fossil traces when in the field, but I felt these two examples would be worth saving. I'm not sure what the official genus and species name is for them but they are nice examples of small worms (maybe trilobites or another arthropod?) burrowing through the Windom shale when it was still mud.

Specimen #1


Specimen #2 has some pyrite preservation.

These specimens were found at a borrow pit on Deep Springs Road in Madison County, NY which exposes the Windom shale member of the Moscow formation (middle Devonian in age, Givetian stage.)

Sunday, April 12, 2020

Mucrosprifier mucronatus from the Moscow formation

One of the most recognizable Brachiopod genus that can be found in the middle Devonian is Mucrospirifer. Below is a specimen of M. mucronatus from the Windom shale member of the Moscow formation. It's a wide hinged shell, often with the hinge line extending farther beyond the main body out into points. This gives the shell a wing like appearance and a friend of mine once told me his daughter called them fossil butterflies. The long hinge line is thought to provide stability for the shell on muddy surfaces where there was not as much of a hard substrate to attach to.

Mucrospirifer is so named due to it's "mucronate" appearance (mucronate is an adjective that means "ending abruptly in a short sharp point or 'mucro'").  That description is based on specimens that have the margin of the shell meeting the hinge line at an acute angle rather than a rounded appearance.The specimen below illustrates that habit well on the right side of the specimen.



There are many different Mucrospirifer species that I have collected from the middle Devonian deposits such as M. arkonensis, M. prolificus, and M. thedfordensis.

But it seems nearly all of the above species were recombined in 1964 by John Tillman ("Variation in Species of Mucrospirifer from Middle Devonian Rocks of Michigan, Ontario, and Ohio", John R. Tillman, Journal of Paleontology, Vol. 38, No. 5 (Sep., 1964), pp. 952-964) into M. mucronatus with the exception of M. thedfordensis. Tillman remarked that "M. thedfordensis (Shimer & Grabau)
differs from M. mucronatus (Conrad) in having a U-shaped to V-shaped sulcus, never with a flattened floor; a low moderately convex fold, never with flattened surface."

Finally, here is an example of M. mucronatus from the Silica shale.

This specimen was found at a borrow pit on Deep Springs Road in Madison County, NY which exposes the Windom shale member of the Moscow formation (middle Devonian in age, Givetian stage.)

Friday, April 10, 2020

Tornoceras uniangulare goniatite from the Moscow formation

Goniatites are primitive Cephalopods that had coiled shells and lived prior to the more well known Ammonites during the Paleozoic. They had chambered shells and can be identified by the suture pattern, as in Ammonites, however the patterns are far simpler than their younger cousins.

Below is a decently sized example of the goniatite Tornoceras uniangulare from the Moscow formation of New York. It is a partial example with a large section of the living chamber missing. I believe it has also been compressed at a slight angle. I'm not sure if it is pareidolia or not but it seems like you can see some of the sutures along the leading edge of the largest chamber (upper left side of the fossil) just before it cuts off.

Specimen #1



A couple of smaller specimens

Specimen #2


Specimen #3


 Sometimes you only find partial sections...

Other times the fossil is warped due to how it was laying in the sediment prior to compression.




These specimens were found at a borrow pit on Deep Springs Road in Madison County, NY which exposes the Windom shale member of the Moscow formation (middle Devonian in age, Givetian stage.)