angeb20 Posted May 7, 2021 Share Posted May 7, 2021 Found this on our small kettle lake shore in southern Minnesota. We occasionally find sea life fossils here, but this is a first for us. Can someone identify? Thank you. Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted May 7, 2021 Share Posted May 7, 2021 Part of the internal mold of an ammonite chamber, I think. 8 Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
daves64 Posted May 7, 2021 Share Posted May 7, 2021 I thought the same thing as soon as I saw the 2nd picture. Accomplishing the impossible means only that the boss will add it to your regular duties. Link to comment Share on other sites More sharing options...
Carl Posted May 7, 2021 Share Posted May 7, 2021 An ammonite sounds strange for Minnesota. Are there Mesozoic outcrops there? I completely agree that this is an ammonite, by the way. Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted May 7, 2021 Share Posted May 7, 2021 1 minute ago, Carl said: An ammonite sounds strange for Minnesota. Are there Mesozoic outcrops there? I completely agree that this is an ammonite, by the way. I thought the same, but then noticed it does say 'glacial till' in the tags. So dragged from elsewhere, I suppose. Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
Carl Posted May 7, 2021 Share Posted May 7, 2021 1 minute ago, Tidgy's Dad said: I thought the same, but then noticed it does say 'glacial till' in the tags. So dragged from elsewhere, I suppose. Aha! Missed that. Thanks! Link to comment Share on other sites More sharing options...
angeb20 Posted May 7, 2021 Author Share Posted May 7, 2021 Thank you everyone for the help. It's so wonderful to have a great resource like this to solve mysteries! Wishing you all a happy weekend! 1 1 Link to comment Share on other sites More sharing options...
minnbuckeye Posted May 7, 2021 Share Posted May 7, 2021 What part of Southern Minnesota was this found in? I live in the SE section which was unglaciated and Ordovician, so no ammonites as pictured. My guess is that you are further west which can be cretaceous.... hence ammonites are possible !! Nice find. SW Minnesota is Cretaceous Ku Undifferentiated—Conglomerate, sandstone, mudstone, shale, marlstone, siltstone, and minor lignite, deposited in marine and non-marine settings; likely Cenomanian to Campanian age. Unit outline is the product of contouring the stratigraphic top and base, from which an isopach grid was created. Because the distribution is patchy, unit boundaries were drawn from the gridded data to represent locations where more than 25 feet (8 meters) of thickness occurs. As a result, many areas outside of the unit boundaries may be overlain by thin Cretaceous strata and the unit is depicted without a contact line. Kc Coleraine Formation—Conglomerate, lignite, sandstone, and shale; shallow marine and nonmarine. Late Cenomanian age is inferred. Despite exposures in mines on the Mesabi Iron Range, the position of much of the unit contact is highly speculative. Ka Claystone, siltstone, and sandstone—An Albian age is tentatively inferred from a single analysis From Geologic Maps of Minnesota 2 Link to comment Share on other sites More sharing options...
angeb20 Posted May 7, 2021 Author Share Posted May 7, 2021 I am in the SW part of MN. Martin County from my understandings, the lake we live on was a small chunk of left behind glacier. We are on the south shore of the lake and have a rough shore of small to medium sized rocks. We find quite a few fossils (starfish pieces, small shell imprints, etc.) this is the most defined so far. I assume they came from Lake Superior way... I haven't studied the glacial range much though. Link to comment Share on other sites More sharing options...
minnbuckeye Posted May 7, 2021 Share Posted May 7, 2021 My guess is the ammonite originated from the Dakotas, probably brought to you from the runoff from Lake Agassiz, a huge glacial lake that drained through your area. The Lake Superior area is not known for ammonites, though there is a tiny spot, the Mesabi range, which has Cretaceous rocks. I am not a geologist, so my opinion is just that, an opinion!!! I would love to see the starfish fossils, an extremely rare fossil. Mike 2 Link to comment Share on other sites More sharing options...
angeb20 Posted May 8, 2021 Author Share Posted May 8, 2021 We get lots of small imprints fossils. The largest was a smaller Mammoth vertebrae. Thank you for the run-off information on the possible ammonite info. So interesting! Link to comment Share on other sites More sharing options...
minnbuckeye Posted May 8, 2021 Share Posted May 8, 2021 This appears to be an interesting coral! Mike 1 Link to comment Share on other sites More sharing options...
Irongiant97 Posted February 28, 2023 Share Posted February 28, 2023 On 5/7/2021 at 5:39 PM, minnbuckeye said: My guess is the ammonite originated from the Dakotas, probably brought to you from the runoff from Lake Agassiz, a huge glacial lake that drained through your area. The Lake Superior area is not known for ammonites, though there is a tiny spot, the Mesabi range, which has Cretaceous rocks. I am not a geologist, so my opinion is just that, an opinion!!! I would love to see the starfish fossils, an extremely rare fossil. Mike Yup, the Coleraine Formation, runs along the southern edge of the Mesabi Range, exposed by iron mines. I volunteer for a paleontology project there. Link to comment Share on other sites More sharing options...
Irongiant97 Posted February 28, 2023 Share Posted February 28, 2023 Im way late but that’s definitely a piece of an ammonite. 1 Link to comment Share on other sites More sharing options...
Irongiant97 Posted April 25, 2023 Share Posted April 25, 2023 OOOHH also is that lake in the southwest corner of the state? Because there is Cretaceous rock down there and some of it is hardly covered by glacial till. Link to comment Share on other sites More sharing options...
Irongiant97 Posted June 8, 2023 Share Posted June 8, 2023 (edited) Update: i talked with a paleontologist and he said the southeast portion of the Cretaceous layer in Minnesota is only about 6ft below the surface so for lakes down there to have these fossils is totally normal. Edited June 8, 2023 by Irongiant97 1 Link to comment Share on other sites More sharing options...
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