Barbara M Posted February 17, 2018 Share Posted February 17, 2018 I spotted this fossil in some Tyndal stone blocks in a building near London Ontario, and am trying to identify what kind of fossil it is. Link to comment Share on other sites More sharing options...
Rockwood Posted February 17, 2018 Share Posted February 17, 2018 Big brachiopod hinge. 1 Link to comment Share on other sites More sharing options...
Kane Posted February 17, 2018 Share Posted February 17, 2018 Looks a bit too large for brachiopod in the Tyndall stone. At times, these can be a challenge to identify due to how the stone is cut, which sometimes obscures rather than reveals key diagnostic features. You will, however, find an abundance of rugose corals, gastropods, Fisherites, orthoconic nautiloids, and Thalassinoides. ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
Rockwood Posted February 17, 2018 Share Posted February 17, 2018 2 minutes ago, Kane said: Tyndall stone In centimeters ? Link to comment Share on other sites More sharing options...
Kane Posted February 17, 2018 Share Posted February 17, 2018 2 minutes ago, Rockwood said: In centimeters ? A scale would definitely help, for sure. Although I don't think I've ever encountered this kind of stone cut into tiny pieces for building purposes. Judging by the mortar, that in itself is usually a fingerprint width. We'll have to wait for the OP to come back and let us know the approximate size! ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
Barbara M Posted February 17, 2018 Author Share Posted February 17, 2018 The base measurement along the bottom, just above the grout is 7.5 inches in length and height is 6 inches. Link to comment Share on other sites More sharing options...
Miocene_Mason Posted February 17, 2018 Share Posted February 17, 2018 Are algal growths or stromatolites ever found here? “...whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been and are being evolved.” ~ Charles Darwin Happy hunting, Mason Link to comment Share on other sites More sharing options...
Rockwood Posted February 17, 2018 Share Posted February 17, 2018 Okay. Humungus not brachiopod hinge. Link to comment Share on other sites More sharing options...
Kane Posted February 17, 2018 Share Posted February 17, 2018 1 minute ago, WhodamanHD said: Are algal growths or stromatolites ever found here? Stromatoporoids are reported in the Tyndall. ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
Miocene_Mason Posted February 17, 2018 Share Posted February 17, 2018 1 minute ago, Kane said: Stromatoporoids are reported in the Tyndall. Than that’s my guess, here’s a Silurian Ontario example, labeled Labechia sp. on this Site: “...whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been and are being evolved.” ~ Charles Darwin Happy hunting, Mason Link to comment Share on other sites More sharing options...
Barbara M Posted February 17, 2018 Author Share Posted February 17, 2018 Thanks. Here are some of the other fossils from the same building. It is interesting in that when the stone was cut, they left the outside facing stone natural and did not cut it smooth so there are lots of dips and protrusions in the stone face. Link to comment Share on other sites More sharing options...
Kane Posted February 17, 2018 Share Posted February 17, 2018 There is a building with Tyndall stone where I work that alternates between saw-cut finish and natural. It is sometimes easier to pick out the details in the saw-cut, and sometimes not. I think I can see in your picture above a very nice, large tabulate coral. ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
Rockwood Posted February 17, 2018 Share Posted February 17, 2018 20 minutes ago, Kane said: I think I can see in your picture above a very nice, large tabulate coral. Agreed. Perhaps the center of a favositid colony ? 1 Link to comment Share on other sites More sharing options...
Kane Posted February 17, 2018 Share Posted February 17, 2018 6 minutes ago, Rockwood said: Agreed. Perhaps the center of a favositid colony ? Possibly, although my ability to identify corals beyond horn and colonial is severely limited! As the Tyndall is Selkirk Member of the Red River Fm, this is a provisional list of corals in it: ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
abyssunder Posted February 17, 2018 Share Posted February 17, 2018 (edited) maybe Cystostroma pictures from here Edited February 17, 2018 by abyssunder add-ons 2 " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
FossilDAWG Posted February 17, 2018 Share Posted February 17, 2018 The link given by abyssunder is very useful for IDing Tyndal stone fossils. The specimen in the OP is something encrusting a shell of some sort. The encruster is likely a stromatoporoid such as Cyclostroma, though Protrochiscolithus (a heliolitid coral) forms dense massive colonies in which individual corallites are difficult to distinguish except in thin sections. What it is that is being encrusted is obscure. The Red River Formation (from which Tyndall Stone is quarried) contains the "arctic Ordovician fauna*", known for the diversity of the fauna and the large size of many species. However, although some of the strophomenid brachiopods get pretty large, none approach 6 or 7 inches in width. Most likely is once of the nautiloids, which get very large. However the lack of structures like camerae or siphuncle make the ID of nautilod quite tentative. That list of corals is very much out of date. As far as favositids are concerned, possibilities include Trabeculites, Crenulites, and Paleofavosites (those are just the ones that people might call "Favosites"). Large flat colonies often turn out to be Trabeculites, but of course one would need to see good sections in which internal details of the corallite structure can be discerned for a confident ID. *The term "arctic Ordovician fauna" reflects the fact that most formations that contain this fauna are exposed in the high arctic, such as on Baffin Island, though it is also found in Manitoba (Red River Formation, Cache Creek Formation), in the Bighorn Mountains of Wyoming, and in the Montoya and Second Value Formations in New Mexico and western Texas. These formations were actually deposited near the Late Ordovician equator. 3 Link to comment Share on other sites More sharing options...
abyssunder Posted February 17, 2018 Share Posted February 17, 2018 Thank you Don, for the comprehensive answer. It looked somehow strange for me and I was not sure about the duality / encrustation (that's the reason why I posted the add-ons), but your opinion confirmed my thought. " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
Kane Posted February 17, 2018 Share Posted February 17, 2018 1 hour ago, FossilDAWG said: That list of corals is very much out of date. As far as favositids are concerned, possibilities include Trabeculites, Crenulites, and Paleofavosites (those are just the ones that people might call "Favosites"). Thanks, Don. The listing I had on hand was quite outdated, but it was the easiest to hand for the RR Fm, Selkirk Mbr. ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
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