Shadow Lake Formation Cephelopod And Others

[clfossils]

Fossils of the Gull River Formation, Black River Group

This past weekend I came across a newly excavated site here in Kingston, Ontario. After spending a few hours over a few days here is what I collected.

Cephelopod - Gull River Formation of the Black River Group, Kingston, Ontario

4.75" x (0.5" to 0.3")

Conulariid - 0.75" x 0.5" - Gull River Formation of the Black River Group, Kingston, Ontario

Thank you to Peter Lee and Nathan Thomas for identifying this for me.

(Daimanella) - Brachiopod - Gull River Formation of the Black River Group, Kingston, Ontario

1.2" x 0.75"

(Ceraurus Cephalon) Trilobite - Gull River Formation of the Black River Group, Kingston, Ontario

1" x 0.75"

(Species Unidentifed Yet) Trilobite - Gull River Formation of the Black River Group, Kingston, Ontario

0.25" x 0.125"

Collected several other specimens that I have not photographed. One in particular, an isotelus pygidium, that I still need to photograph.

I'm always wanting to make sure I have the right species names. If you know of an error please let me know. I have been learning a lot from everyone on this forum.

THANK YOU

[lissa318]

Nice finds! Congrats!

[squalicorax]

Very nice stuff

Nathan

[FossilDAWG]

Nice finds, it's hard to find anything in the Shadow Lake.

I'm pretty sure your "Cerarus" is a Bathyurus, and so is your last photo. I'll have to check the species later, some have a smooth glabellum and some are quite pustulose.

The cephalopod is none too well preserved, but it has some features that suggest it is an actinocerid.

I agree with the conularid ID, but the ornament looks a little unusual. I might have a reference to narrow the ID down better.

Don

[clfossils]

Thank you everyone.

(Thank you Don) I'm very interested to figure out the cephalopod. The bottom part of it seems almost oil looking, in detail it looks like there are parts associated with the bottom section. I'll have to get some closer photos and post them.

[piranha]

How about another bathyurid trilobite: Raymondites? Attached for comparison are two examples from the Gull River Fm (Black River Group) of Ontario. We had a discussion on these a while back and Geodigger provided the photo on the right for R. longispinus. Thanks for another batch of fantastic fossils and photos!

[clfossils]

Question: I examined a few maps of the various Formations associated with the Black River Group. The two were the Gull River Formation and the Shadow Lake Formation. How do you know for certain that you are in the Shadow Lake Formation? Everything seemed to point me in that direction, with the shale and the depth at which I found them.

THANK YOU

[piranha]

Question: I examined a few maps of the various Formations associated with the Black River Group. The two were the Gull River Formation and the Shadow Lake Formation. How do you know for certain that you are in the Shadow Lake Formation? Everything seemed to point me in that direction, with the shale and the depth at which I found them.

THANK YOU

Geology and lithostratigraphy are not my best subjects but I found a few papers that should be useful. Part 2 of the AJS paper has a table with dozens of detailed Ontario localities as well as the expected faunas. The Lowville and Pamelia formations in NY appear to be the BRG equivalent for Shadow Lake and Gull River respectively. You will have to correlate the older charts and tables with the current standards. Here is a list of papers you might want for additional research:

Young, F.P. (1943)

Black River stratigraphy and faunas, Part 1.

American Journal of Science 241(3):141-166

Young, F.P. (1943)

Black River stratigraphy and faunas, Part 2.

American Journal of Science 241(4):209-240

Cameron, B., & Mangion, S. (1977)

Depositional environments and revised stratigraphy along

the Black River-Trenton boundary in New York and Ontario.

American Journal of Science 277(4):486-502

Brett, C.E., & Brookfield, M.E. (1984)

Morphology, faunas and genesis of Ordovician hardgrounds from southern Ontario, Canada.

Palaeogeography, Palaeoclimatology, Palaeoecology 46(4):233-290

Brookfield, M.E. (1988)

A mid-Ordovician temperate carbonate shelf-the Black River

and Trenton Limestone Groups of southern Ontario, Canada.

Sedimentary Geology 60(1):137-153

[Missourian]

Nice close-ups of some cool fossils.

[FossilDAWG]

Scott,

I thought about Raymondites, which is very close to Bathyurus, but my understanding is that Raymondites has a spine on the occipital ring which extends over the axis of the thorax. Of course that structure is pretty fragile and is often broken off, but usually you can at least see the base of the spine, as in the first of the photos you posted. I don't see a spine base in clfossil's "Cerarus" photo, but the photo isn't taken from the perfect angle to be sure.

Don

[piranha]

Scott,

I thought about Raymondites, which is very close to Bathyurus, but my understanding is that Raymondites has a spine on the occipital ring which extends over the axis of the thorax. Of course that structure is pretty fragile and is often broken off, but usually you can at least see the base of the spine, as in the first of the photos you posted. I don't see a spine base in clfossil's "Cerarus" photo, but the photo isn't taken from the perfect angle to be sure.

Don

Raymondites spiniger has the occipital spine. R. longispinus does not and named instead for its lengthy genal spines.