Toronto (Upper Ordovician) Fossil ID

[amaanthawer]

Hey everyone! I found my first fossil last weekend in a creek near the Don River in midtown Toronto. From my knowledge reading through this forum, it seems to be packed with crinoid stem fossils. I’d really appreciate a confirmation, to learn more about the age of the fossil and maybe even the species. 

[Thomas.Dodson]

The majority are indeed crinoid columnals and there also appears to be worn coral (pic 2 and 3). I took a look at a geologic map of Toronto but I can't confirm your formation. I don't see outcrops of the Georgian Bay in Toronto but only farther West around Mississauga. Still, there aren't any other Paleozoic outcrops listed so it could be a remnant, unrecorded outcrop, or an outdated map issue. Hopefully someone more knowledgeable of the area will know more. @Kane?

 

http://www.geologyontario.mndm.gov.on.ca/mndmfiles/pub/data/imaging/P2204/p2204.pdf

[Kane]

This does have the look of Georgian Bay Fm material, which would put it in the upper Ordovician. From my understanding, there are no outcrops per se (possibly some material dug up if they've been working on the subway) and some erratics along the Don River. 

[JUAN EMMANUEL]

Hello, I collected Georgian Bay formation material before moving south west to Hamilton. 

 

This doesnt look like Georgian Bay formation material. It reminds me more of imported rocks/rubble the city would use as a buffer against water erosion. Years ago I managed to pin down what rock formation this came from (and it is from Ontario, just not the local Georgian Bay formation) but I forgot what it was. This rock would have been transported there to the Don River.

 

If you want to compare it to the local lithology of the Georgian Bay formation, you should head to the Don Valley Brickworks and compare the rock to the exposed Georgian Bay formation shale there.

Edited May 24, 2021 by JUAN EMMANUEL

[Ludwigia]

I once found similar pieces many years ago at a construction site on the Caledon/Brampton border and managed with the help of advice from colleagues to narrow them down to the Middle Silurian Lockport Group, Gasport/Amabel Formation. Never did find out the name of the crinoids though.