Rockwood Posted May 26, 2019 Share Posted May 26, 2019 9 minutes ago, TqB said: Unusual but not unknown I believe Agreed. It seems like Iv'e read (maybe Seilicher) of a preservation bias that may be the cause. I don't remember just what it may have been though. 1 Link to comment Share on other sites More sharing options...
Plantguy Posted May 26, 2019 Share Posted May 26, 2019 2 hours ago, TqB said: Unusual but not unknown I believe, especially when the outer shell is fragile and the siphuncle robust. Or the septa could have been obscured/lost, as in parts of this 7" Carboniferous Pseudactinoceratid I photographed in the field. Anyway, it was only a tentative suggestion. Very cool! Regards, Chris Link to comment Share on other sites More sharing options...
Plantguy Posted May 26, 2019 Share Posted May 26, 2019 (edited) I wonder if a clearer picture could be obtained...looks like there are alot of details there that are not in focus. Do you think having these in sharp focus would provide an answer? Sorry for the double entry...thought I was editing the former post... Regards, Chris Edited May 26, 2019 by Plantguy I goofed again apparently Link to comment Share on other sites More sharing options...
Rockwood Posted May 26, 2019 Share Posted May 26, 2019 46 minutes ago, Plantguy said: Do you think having these in sharp focus would provide an answer? Could even make it a sponge ? Link to comment Share on other sites More sharing options...
Mark Kmiecik Posted May 26, 2019 Share Posted May 26, 2019 I looked at the original post again because this thread has piqued my curiosity and I'd like to offer another possibility. Notice that I said "possibility". Could this be the mold of a fish spine? Mark. Fossil hunting is easy -- they don't run away when you shoot at them! Link to comment Share on other sites More sharing options...
Rockwood Posted May 26, 2019 Share Posted May 26, 2019 4 minutes ago, Mark Kmiecik said: Could this be the mold of a fish spine? It wouldn't be that far off for a chondrichthyan. Would it ? Link to comment Share on other sites More sharing options...
Mark Kmiecik Posted May 26, 2019 Share Posted May 26, 2019 (edited) 33 minutes ago, Rockwood said: It wouldn't be that far off for a chondrichthyan. Would it ? That was my thought. It would explain the regularity of individual members segments. Edited May 26, 2019 by Mark Kmiecik added strikethrough and replacement Mark. Fossil hunting is easy -- they don't run away when you shoot at them! Link to comment Share on other sites More sharing options...
ynot Posted May 26, 2019 Share Posted May 26, 2019 29 minutes ago, Mark Kmiecik said: Could this be the mold of a fish spine? I see nothing of other bone parts and the separation is flat where a fish vert has a cone shaped separation. I do not see anything fishy about this. Darwin said: " Man sprang from monkeys." Will Rogers said: " Some of them didn't spring far enough." My Fossil collection - My Mineral collection My favorite thread on TFF. Link to comment Share on other sites More sharing options...
Mark Kmiecik Posted May 26, 2019 Share Posted May 26, 2019 10 minutes ago, ynot said: where a fish vert has a cone shaped separation Yes, but we're only seeing the edges of the mold. It may have indeed conical at some point in time. Mark. Fossil hunting is easy -- they don't run away when you shoot at them! Link to comment Share on other sites More sharing options...
ynot Posted May 26, 2019 Share Posted May 26, 2019 38 minutes ago, Mark Kmiecik said: Yes, but we're only seeing the edges of the mold. It may have indeed conical at some point in time. When You look at the side of a cone You see a triangle, not a flat line. I can not see any way that this could be from a fish. Darwin said: " Man sprang from monkeys." Will Rogers said: " Some of them didn't spring far enough." My Fossil collection - My Mineral collection My favorite thread on TFF. Link to comment Share on other sites More sharing options...
Mark Kmiecik Posted May 26, 2019 Share Posted May 26, 2019 42 minutes ago, ynot said: When You look at the side of a cone You see a triangle, not a flat line. What do you see when you look at the side of a cone that isn't there anymore? The edge of the disc is a flat line. Mark. Fossil hunting is easy -- they don't run away when you shoot at them! Link to comment Share on other sites More sharing options...
Rockwood Posted May 26, 2019 Share Posted May 26, 2019 10 minutes ago, Mark Kmiecik said: What do you see when you look at the side of a cone that isn't there anymore? The edge of the disc is a flat line. There is an image on the net of a cane fashioned from a shark spine. Strait as an arrow. Link to comment Share on other sites More sharing options...
Mark Kmiecik Posted May 26, 2019 Share Posted May 26, 2019 I submit this: Imagine a mold of this, then remove everything except 25% of the diameter, then remove everything except the edge of that 25%. Mark. Fossil hunting is easy -- they don't run away when you shoot at them! Link to comment Share on other sites More sharing options...
ynot Posted May 26, 2019 Share Posted May 26, 2019 44 minutes ago, Mark Kmiecik said: What do you see when you look at the side of a cone that isn't there anymore? The edge of the disc is a flat line. If the cone is a replacement of the cartilage between the verts it would be one solid piece. How would it erode to a flat plane? 33 minutes ago, Rockwood said: There is an image on the net of a cane fashioned from a shark spine. Strait as an arrow. But does it show internal structures? 15 minutes ago, Mark Kmiecik said: I submit this: What do skateboard wheels have to do with this discussion? Darwin said: " Man sprang from monkeys." Will Rogers said: " Some of them didn't spring far enough." My Fossil collection - My Mineral collection My favorite thread on TFF. Link to comment Share on other sites More sharing options...
Mark Kmiecik Posted May 26, 2019 Share Posted May 26, 2019 2 minutes ago, ynot said: What do skateboard wheels have to do with this discussion? Snarge, I thought I was drawing shark vertebra. Maybe I'll get a job as a skateboard wheel designer. Mark. Fossil hunting is easy -- they don't run away when you shoot at them! Link to comment Share on other sites More sharing options...
ynot Posted May 26, 2019 Share Posted May 26, 2019 Another thing- why do the insides of the (supposed) fish vert molds show a flat surface with no characteristics of a fish vert mold? Darwin said: " Man sprang from monkeys." Will Rogers said: " Some of them didn't spring far enough." My Fossil collection - My Mineral collection My favorite thread on TFF. Link to comment Share on other sites More sharing options...
Mark Kmiecik Posted May 27, 2019 Share Posted May 27, 2019 56 minutes ago, ynot said: Another thing- why do the insides of the (supposed) fish vert molds show a flat surface with no characteristics of a fish vert mold? Note how 90%-ish of the circumference can be featureless. Mark. Fossil hunting is easy -- they don't run away when you shoot at them! Link to comment Share on other sites More sharing options...
Mark Kmiecik Posted May 27, 2019 Share Posted May 27, 2019 This sequence of wear explains it all: Note how the conical features disappear. Mark. Fossil hunting is easy -- they don't run away when you shoot at them! Link to comment Share on other sites More sharing options...
ynot Posted May 27, 2019 Share Posted May 27, 2019 OK, so now it is not a bony fish but a shark? I would still expect to see some features within the "mold" to indicate a vert. There are none. As for the cone, explain how a flat wall is left within the mold as is in the OP's piece. (Top segment where Plantguy put a red arrow.) 13 hours ago, Plantguy said: I wonder if a clearer picture could be obtained...looks like there are alot of details there that are not in focus. Do you think having these in sharp focus would provide an answer? Sorry for the double entry...thought I was editing the former post... Regards, Chris @younggunz Can We see some better focuses picture, please? Darwin said: " Man sprang from monkeys." Will Rogers said: " Some of them didn't spring far enough." My Fossil collection - My Mineral collection My favorite thread on TFF. Link to comment Share on other sites More sharing options...
Mark Kmiecik Posted May 27, 2019 Share Posted May 27, 2019 I'm still not sure of anything, just stating possibilities. I agree that better photos may be more diagnostic. Mark. Fossil hunting is easy -- they don't run away when you shoot at them! Link to comment Share on other sites More sharing options...
Rockwood Posted May 27, 2019 Share Posted May 27, 2019 2 hours ago, ynot said: But does it show internal structures? Kind of the point. No it doesn't, but that would mean they might be filled in with more mobile/soluble material that wouldn't necessarily be distinguishable in a mold fossil. Link to comment Share on other sites More sharing options...
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