Sunday, July 5, 2020

Small sponge from the Widder formation

On a trip to the exposures of the Widder formation along the Credit river in Hungry Hollow, Ontario, I found this cluster of sponge spicules. It is not uncommon to find individual spicules like this within the Hungry Hollow member of the Widder formation, but a large cluster like this is less common. I checked the "Check List of Fossil Invertebrates Described from the Middle Devonian Rocks of the Thedford-Arkona Region of Southwestern Ontario" by Stumm and Wright (1958) and they list one sponge known from the Widder formation: Astraeospongia hamiltonensis.  I am familiar with that genus from the upper Silurian where it is known as Astraeospongia meniscus from the Brownsport formation. The spicules in my specimen look very similar to those earlier species so I think I will stick with the name Astraeospongia hamiltonensis.



I collected this specimen from the Hungry Hollow member of the Widder formation which is Devonian in age, Givetian stage.




Thursday, July 2, 2020

Mystery echinoderm from the Verulam formation

Below are some pictures of a mystery Echinoderm from the Verulam/Bobcaygeon formation. I am not entirely sure of the formation this comes from as it was found in an area that was close to the boundary of the two units.

It was found a couple of years ago and cleaned by an expert but there it not much there to go on. I posted these images to a group on Facebook that is frequented by knowledgeable people who have collected for many years from the Verulam and Bobcaygeon formation. The only possibility that was suggested was that it could have been part of the central body of a starfish. The presence of many small plates does make it seem like an echinoderm and starfish have lots of small plates as part of their bodies so I think this is as close as I'll be able to get to figuring out just what this was. For reference, the fossil is about the size of a US quarter.





I collected this fossil in 2017 at the James Dick quarry near Gamebridge, Ontario. The Verulam and Bobcaygeon formation is late Ordovician in age, Katian/Mohawkian stage.

Monday, June 29, 2020

Ceraurus globulobatus Trilobite from the Verulam formation

I've mentioned before that I don't often have luck with finding Trilobites, well the specimen below is a definite exception to the rule. It's a Ceraurus globulobatus from the Verulam formation. I found it a few years back and a friend, M.T., did the prep work to clean it up. It's not a perfect specimen but it's darn nice. The glabella is slightly crushed and one of the tail spines is missing as well as a small section of shell from the end of the thorax. All in all though, it's a large fossil and a species I never had before.





It is a very flat specimen so perhaps more evolved to swim in the water column?

The eyes are fairly well preserved and not crushed. I am not able to see any lenses though.

Here is what it looked like before it was cleaned up.


I collected this fossil in 2017 at the James Dick quarry near Gamebridge, Ontario. The Verulam formation is late Ordovician in age, Katian/Mohawkian stage.

Friday, June 26, 2020

Cupulocrinus jewetti crinoid from the Bobcaygeon Fm.

This is a partial Crinoid from the Bobcaygeon formation in Gamebridge, Ontario, Canada. I found it a few years ago on a field trip and a friend, Malcolm, cleaned it up for me. The crinoid is named Cupulocrinus jewetti and this is a pretty good example. The stem and some arms are missing but otherwise it is a decent specimen.  It is one of the few articulated crinoid specimens that I have found myself.




The Bobcaygeon formation is Ordovician in age (late Ordovician, Katian/Mohawkian stage).
I used William Hessin's book "South Central Ontario Fossils", 2009, Self Published, pg. 244 to help identify this fossil.

Wednesday, June 24, 2020

Syringocrinus paradoxicus carpoid plate from the Verulam formation

A number of years ago I picked up a large plate of shaly limestone at the James Dick quarry in Gamebridge, Ontario. It comes from the Verulam formation and I knew it was a special find as I could see what looked like crinoid stems on it but with slightly different shapes to the stems. It turns out that after a good cleaning by my friend Malcolm the crinoid stems are actually carpoid stems. Carpoids are odd echinoderms that are cousins to crinoids. These particular fossils are called Syringocrinus paradoxicus and are fairly rare to find. There are no complete specimens on the plate but plenty of stems and calyx plates scattered about. 










As a bonus, there is a small Archaeocrinus sp. crinoid off to one side of the plate. Thanks go out to Kevin B. for the ID on this small fossil (the calyx is maybe 1cm in width).




The Verulam formation is Ordovician in age (late Ordovician, Katian/Mohawkian stage).

Tuesday, June 23, 2020

Cycloconcha milleri pelecypod from the Marble Hill Bed

I've only found one Pelecypod in the "Marble Hill Bed" and it called Cycloconcha milleri.  I knew in a previous post that the genus was Cycloconcha but could not find anything to nail down the species. I finally came across a research report, by PM Novack-Gottshall and A. Miller, that listed Cycloconcha milleri as being found in the "Marble Hill Bed".

Part of the reason I could not settle on a species name is the lack of good photos of the species.  The Atlas of Ordovician Life only had this nondescript picture, and the UGA Stratigraphy Lab did not have much more. These are two of the online resources I use to help ID fossils from the Cincinnati region but I can't blame them for the lack of information. Pelecypods don't always preserve well and are not easily studied as the more common and well preserved Brachiopods in the Ordovician.  Also the "Marble Hill Bed" is a very limited geologic feature and not as paleontologically or economically important as other formations.

Onto the fossils!

Specimen #1 - right valve exterior
 Right valve interior, note the hinge teeth

Specimen #2  - Left valve exterior
 Left valve interior
 Left valve profile looking at the anterior end towards the posterior


The "Marble Hill Bed" is part of the Rowland Member of the Drakes formation (equivalent the Whitewater formation in Ohio and Indiana). It is upper Ordovician in age, Katian stage (450-445 mya) and located near Carrollton, KY. I collected these fossils in July of 2016.

Sunday, June 21, 2020

Clathrospira subconica gastropod from the Marble Hill Bed.

Clathrospira subconica is another common gastropod fossil that is found in the Marble Hill Bed. It is not nearly as common as Paupospira bowdeni but good examples are not hard to find.  This is another high spired, conispiraled gastropod but it is shorter and fatter than Paupospira bowdeni. The shell opening is triangular in shape and this results in a somewhat sharp edge to each spiral.

Specimen #1





Specimen #2






The "Marble Hill Bed" is part of the Rowland Member of the Drakes formation (equivalent the Whitewater formation in Ohio and Indiana). It is upper Ordovician in age, Katian (Richmondian) stage (450-445 mya) and located near Carrollton, KY. I collected these fossils in July of 2016.

Friday, June 19, 2020

Paupospira bowdeni gastropod from the Marble Hill Bed

I made a post a while back about some fossils that friends of mine had sent me from a curious locality called the "Marble Hill Bed". This post is part of a series meant to focus on the individual specimens that come from that location. Today we are looking at Paupospira bowdeni, a high turrented conispiral gastropod. This is the most common fossil found in the "Marble Hill Bed" with hundreds of individuals to be found in matrix or eroded free. The often preserve the majority of their 3D shape but generally show some compression in one axis. The opening and living chamber are tube shaped.

Specimen #1





Specimen #2





Here are some as they lie exposed on the ground, weathered free from the rock.

The "Marble Hill Bed" is part of the Rowland Member of the Drakes formation (equivalent the Whitewater formation in Ohio and Indiana). It is upper Ordovician in age, Katian (Richmondian) stage (450-445 mya) and located near Carrollton, KY. I collected these fossils in July of 2016.