Fossils Imprints On Lake Winnipeg, Manitoba

[boswachter]

Hi all,

Here is goes, finally I found a place "alive" enough to talk about fossils. Most other places I saw were just as alive as the fossils they were supposed to talk about.

Sohere I went on a trip onto an island in Lake Winnipeg in Manitoba, Canada. The ground is shale or limestone. Just walking on the "beach" I came across a bunch of fossils or imprints of fossils. Now I tried to find out how old that particular spot was and came up with Ordovician.

Here are the images of what I saw:

1:

2:

This one looks like a fish, but I doubt is a fish would leave such a lasting imprint

3:

This one has my size 12 shoe in it for measure, but I saw the same type of imprint that was at least 5 to 6 feet long.

4:

Can anyone point me in the right direction or even identify these fossils for me?

Thanks,

Henk

Edited July 3, 2015 by boswachter

[Raggedy Man]

2 and 3 appear to be cephalopod imprints. 1 and 4 look like ammonites to me, but could also be gastropods(snails). Someone who has an eye better trained should be along soon to either confirm or dismiss my general identification. Either way, you came to the right place! Wonderful finds!

Best regards,

Paul

Edited July 3, 2015 by Raggedy Man

[Auspex]

Your beach does speak of life; cephalopods and snails, I think.

[abyssunder]

IMO,#2 looks more like imprints, so I incline to believe that they are trace fossils.

I agree with Paul.

Edited July 3, 2015 by abyssunder

[howard_l]

No Ammonoid if this is Ordovician and it looks like it. The gastropod looks like Maclurites. The cephalopod could be Endoceras because of the size.

[FossilDAWG]

I'm confident you are looking at the Selkirk Member of the Red River Formation, which is of Late Ordovician age. The same rocks are exposed in the quarries at Garson and Tyndal, where "Tyndal Stone" is produced for building stone. Tyndal Stone is famous for the numerous large fossils of gastropods, cephalopods, and corals.

Your first and fourth photos are of a large snail, Maclurites manitobensis. This species is actually the largest known Ordovician snail in the world. The second and third photos are a straight-shelled (orthoconic) nautiloid cephalopod, a distant relative of the modern pearly nautilus. It would be impossible to identify the species from the photos, as the Red River formation contains over 30 described species of cephalopods, and diagnostic characters such as the suture and siphuncle are not shown on the specimen you photographed. However, the Red River Formation is well known for the extremely large size of most of the fossils, a characteristic of the "Arctic Ordovician Fauna" that is found in related rocks in the Arctic (Greenland, Baffin and Meville Islands), at places around Hudson's Bay near Churchill, to the West in the Rocky Mountains, and to the southwest in the Bighorn Mountains in Wyoming and in the Montoya Formation in southern New Mexico and adjacent Texas near El Paso. Despite the "arctic" element, the fauna is actually tropical as the equator ran through those areas in the Late Ordovician. Although Endoceras did grow to a large size, most of the cephalopods in the Red River Formation are large (even gigantic), Endoceras is present but relatively rare, and Endoceras is characterized by a long straight siphuncle with short septal necks that filled most of the volume of the shell. In fact most Endoceras fossils consist of only the siphuncle, as this ws the most robust part of the shell and the remainder of the shell was more fragile. The specimen you photographed does not show these features, and it is probably not Endoceras.

It looks like you have found a good exposure of the Red River Formation. If you get the chance to go back, it would be great if you posted more photos of the fossils. There are also Silurian and Devonian rocks with quite different fossils exposed around the lake.

Don

[boswachter]

Thank you all for the identification, from there I can find more information (the web is a beautiful place for that).

I will be going back to this place, it's an uninhabited island called Black Bear Island near the narrow part of Lake Winnipeg. I will be posting more pictures of other finds. Thanks again!