Help me understand what I am looking at please

Discussion in 'Cephalopod Fossils' started by anothersquid, Mar 14, 2013.

  1. anothersquid

    anothersquid O. bimaculoides Supporter

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    I have a large artistic sort of carving that is laced with Orthoceras fossils. I've attached a picture of one of the larger fossils.

    Now, the shell of the animal fossilizes well and that's easy enough to see. What I'm wondering is if the much-less-clear stuff at the big end of the shell is actually fossilized fleshy bits that managed to mineralize enough to leave an impression.

    I know that the fleshy bits of, well, anything really, don't usually fossilize well, so I'm wondering if I have a fairly cool fossil squid relative, or a cool fossil shell with random junk at the end.

    any thoughts would be appreciated.

    Thanks.

     

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  2. Terri

    Terri Sepia elegans Registered

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    Hello anothersquid! Interesting piece you have there, I think you have come to a pretty good understanding of what's going on here with the statement that you have a "cool fossil shell with random junk at the end".:heee: There are some interesting discussions in some of the threads (and photos) in this forum http://www.tonmo.com/forums/forumdisplay.php?103-Soft-Part-Preservation . I could be wrong and if so Kevin will check in at some point and straighten things out. :smile:

    Very nice piece though, thanks for posting!
     
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  3. anothersquid

    anothersquid O. bimaculoides Supporter

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    I realize I don't have anything that gives scale in that picture, really. The shell marked in red is about 19 cm long and 2 cm wide at the end where the random junk is.
     
  4. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

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    Considering the preservation of the rest of the matrix around all the other fossils, it looks like only shells and parts of shells are preserved. The open end of cephalopod shells are good places for small shells and bits of shells to collect when there is a fairly strong current, a current strong enough to align the longer shells. I think that is what you have, just the collection of shell bits in the open end of a shell.
     
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  5. Pr0teusUnbound

    Pr0teusUnbound GPO Registered

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    you might want to bear in mind that the white stuff in black Orthoceras-bearing limestone you have is probably the mineral calcite. calcite crystals often form on the inside of fossilized shells and exoskeletons (much like a geode). soft parts are usually preserved as carbon, phosphorus, iron or pyrite, but ive never heard of organic tissues being preserved as calcite, so the white stuff you probably isnt soft tissue.

    what white calcite crystals DO indicate are empty spaces. notice how the Orthoceras fossils are white blocks in a line with nothing in between? the actual shell of the animal disintegrated after the gas chambers filled in with calcite crystals. the same thing happens other animals with a similar shell composition. the white circles in the area you circled might be gastropods, but im not sure about the other "fleshy" shapes.
     
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