Wednesday, April 8, 2020

Glyptomaria capillaria gastropod from the Moscow formation

Today I have a well preserved example of the Gastropod Glyptomaria capillaria that I found in the Windom shale member of the Moscow formation. It is a high spired shell with a cross hatch kind of patterning along the whorls (a mix of growth lines and striae) and three relatively distinct lines that run in parallel to the whorls. The specimen below is a cast still embedded in shale but is nicely displayed for an easy ID





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.)

Monday, April 6, 2020

Spryoceras sp. cephalopod from the Moscow formation

Spyroceras sp. is a genera that is known from the Ordovician period up through the Devonian period. that gives it an age range of 100 million years that the genus is recognized in the fossil record. It's doubtful that a single species lasted that long, but it does speak to the success of the genus.  Below is an example of the genus that I found at the Deep Springs Rd. borrow pit in New York. It comes from the Windom shale member of the Moscow formation (middle Devonian, Givetian stage). It is easily recognized by the straight, orthoconic shell that has regularly spaced growth rings that are perpendicular to the rest of the shell. If there was enough detail on the impression I might be able to narrow down the species based on the presence of striae that can sometimes be seen between the growth rings but are parallel to the shell's growth.

Specimen #1


This is a 3-D fossil cast of the shell so it pops off and you can see both sides.

Specimen #2 - This may be a different species, perhaps Spyroceras nuntium which is known for having more closely spaced annulations and coarser striae.





I found an example of Spyroceras sp. in the Ordovician aged Verulam formation here (scroll to the bottom of the post).

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.)

Saturday, April 4, 2020

Devonochonetes coronatus brachiopod from the Moscow formation

Devonochonetes coronatus is a very common fossil in the Moscow formation of New York. It's easy to identify as it is the largest of the Chonetid type brachiopods found in the middle Devonian. The shell is rectangular in outline, the pedicle valve is convex while the brachial valve is concave. A straight hinge line runs the length of the posterior and sometime you will find spines, or the bases of them, along the pedicle valve.

Specimen #1 - Pedicle valve

Anterior
Brachial valve
Posterior
Profile
Hinge line with spine bases

Specimen #2 - Pedicle valve
Anterior
Brachial valve - note the impression of a Protoleptostrophia perplana brachiopod that covers the Brachial valve.
Posterior
Profile

This specimen is interesting due to the damage to the brachial valve. It exposes the interior of the brachial valve, the sediment that filled in where the animal used to live, and the interior of the pedicle valve. The layering is interesting and shows you just how little space the animal had to live in.



Compare this specimen to one from the Silica shale.

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.)

Thursday, April 2, 2020

Palaeoneilo emarginata pelecypod from the Moscow formation

One of the easier pelecypods to ID from the middle Devonian is Palaeoneilo emarginata. It is an oval shaped shell with wide growth rings. The specimen below comes from the Windom shale member of the Moscow Formation at the Deep Springs Rd. borrow pit.



Compare this specimen to one from the Mahantango formation,  or from elsewhere in the Moscow formation.

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, March 31, 2020

Devonochonetes scitulus brachiopod from the Moscow formation

In a previous post I wrote about specimens of Devonochonetes scitulus that I'd found with spines still present. The spine positions, angles, and number are the best way to differentiate between species of Devonochonetes. The previous specimens came from the Ludlowville formation and below is a specimen from the Moscow formation at the Deep Springs Rd. borrow pit. The Ludlowville underlies the Moscow formation and so is contemporaneous which means it is not unexpected to find this species at this location.

Specimen #1


Specimen #2


Here is a specimen that shows the interior of the brachial valve. The oval shapes visible are the muscle scars where the brachials would have been attached. As the brachials were not mineralized in this species, only the marks on the shell where they used to be are preserved.





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, March 29, 2020

Protoleptostrophia perplana brachiopod from the Moscow formation

Protoleptostrophia perplana is not an uncommon Brachiopod fossil in the middle Devonian but what is uncommon is to be able to find an intact specimen that is not a mold in the rock.  Below is a fairly good specimen of the species that has a valve preserved in calcite. It comes from the Deep Springs Road borrow pit in near Earlville, NY.  It is not 100% intact as the margin shows a rough edge which is likely due to the very thin and fragile nature of the 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.)

Friday, March 27, 2020

Calymene celebra Trilobite from the Joliet formation

Calymene celebra is the state fossil of Wisconsin and a somewhat common fossil in the white/light grey/tan Silurian aged dolostones that can be found across a number of midwest states. Rocks like this stretch from Wisconsin and Iowa down through Illinois and Indiana into Kentucky.  Below is a specimen of  Calymene celebra from the Joliet formation near Grafton Illinois. It was likely found in a quarry as productive exposures of the Joliet formation are not easy to find. 

This fossil is a cast of the interior of the trilobite exoskeleton so it's missing some of the details one would normally see.  I like this specimen due to the presence of black specks that are present. It kind of reminds me of a Dalmation dog's coat.  I think the black spots are oxidized Pyrite or Marcasite.









I've been fortunate enough to find one specimen of Calymene celebra myself. It comes from a breakwater along Lake Michigan in Milwaukee, Wisconsin where I spotted it among the rocks being used to stabilize the shoreline. It was in a small flat slab so I didn't have to smash anything to collect the specimen. You can see that it was exposed for a time as one side is smooth and some of the fossil detail has been lost.  Since the rocks had been moved from their original location, I am not sure what formation this fossil comes from.







These fossils come from the Silurian period, Llandovery stage (roughly 438-436 mya) which corresponds to the basal Niagaran series in the old N. American chronostratigraphy.

Wednesday, March 25, 2020

Hardouinia kellumi echinoid from the Pee Dee formation

Echinoids are cool critters that come in two basic flavors, regular and irregular. The regular echioids are the ones you see in aquariums and on nature shows with the long spines crawling along the bottom of the reef. Irregular echinoids are more often partially submerged in the sediment and do not have large showy spines.  Hardouinia kellumi is an example of an irregular urchin and could also be known as a sea biscuit.  The specimen below is from the Cretaceous ages sediments at Rocky Point Quarry in North Carolina. It comes from the Peedee formation which is dated to the late Maastrichtian (66-67 mya)

Adaptical surface

Anterior

Left profile

Posterior

Right profile

Adoral surface