Michelle Sawicki Library Posted July 7, 2017 Share Posted July 7, 2017 Now that the ticks have died back a bit I am back to fossil hunting. Is this a worm? Link to comment Share on other sites More sharing options...
ynot Posted July 7, 2017 Share Posted July 7, 2017 No it is not a worm. My best guess is a broken crinoid columnal. 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...
TqB Posted July 7, 2017 Share Posted July 7, 2017 I agree with ynot - the ridged, articulating surface of a crinoid columnal. What diameter is it? Tarquin Link to comment Share on other sites More sharing options...
Kane Posted July 7, 2017 Share Posted July 7, 2017 I agree with the others that this is likely a crinoid columnal. ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
Herb Posted July 7, 2017 Share Posted July 7, 2017 +1 for crinoid columnal "Absence of evidence is not evidence of absence"_ Carl Sagen No trees were killed in this posting......however, many innocent electrons were diverted from where they originally intended to go. " I think, therefore I collect fossils." _ Me "When you have eliminated the impossible, whatever remains, however improbable, must be the truth."__S. Holmes "can't we all just get along?" Jack Nicholson from Mars Attacks Link to comment Share on other sites More sharing options...
abyssunder Posted July 7, 2017 Share Posted July 7, 2017 I agree. Crinoid columnal facet, showing the crenulae. " 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...
Gen. et sp. indet. Posted July 7, 2017 Share Posted July 7, 2017 I disagree. Rugosa, IMHO. Link to comment Share on other sites More sharing options...
westcoast Posted July 7, 2017 Share Posted July 7, 2017 I don't see a Crinoid columnal breaking like this. It looks more like something hollow.... Link to comment Share on other sites More sharing options...
Al Dente Posted July 7, 2017 Share Posted July 7, 2017 I also think it is a rugosan. Link to comment Share on other sites More sharing options...
Kane Posted July 7, 2017 Share Posted July 7, 2017 I think coral is possible, but some of the terminations in this specimen seems to speak of crinoid. I've found several crinoid bits that are broken and displaced. The crenellations seem very similar to crinoidal. But they could also be suggestive of coral septae. We need more info on size to get a better assessment, methinks. ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
Wrangellian Posted July 7, 2017 Share Posted July 7, 2017 Until we get an answer on the size, I have a hunch the photo is magnified, just by the look of it, so it's probably not too large for a crinoid columnal. Link to comment Share on other sites More sharing options...
izak_ Posted July 7, 2017 Share Posted July 7, 2017 I agree with horn coral. The sediment in the very middle is unusual. Link to comment Share on other sites More sharing options...
westcoast Posted July 7, 2017 Share Posted July 7, 2017 Need to remove at least some of the matrix in the centre to know for sure. Doesn't look like that is a real option however. Link to comment Share on other sites More sharing options...
Michelle Sawicki Library Posted July 8, 2017 Author Share Posted July 8, 2017 It is about the size of a nickel. Link to comment Share on other sites More sharing options...
Kane Posted July 8, 2017 Share Posted July 8, 2017 I think the size may rule out crinoid and put coral into the running. ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
ynot Posted July 8, 2017 Share Posted July 8, 2017 1 hour ago, Kane said: I think the size may rule out crinoid and put coral into the running. I disagree, there are crinoids well over 1 inch across. The way that the internal curve mirrors and remains parallel to the outside curve is not something I have seen in a coral. Also I do not see that many septae in a coralite. I stick with a crinoid fragment. 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...
Kane Posted July 8, 2017 Share Posted July 8, 2017 Just now, ynot said: I disagree, there are crinoids well over 1 inch across. The way that the internal curve mirrors and remains parallel to the outside curve is not something I have seen in a coral. Also I do not see that many bars in a coralite. I stick with a crinoid fragment. Then I'll have to shift my money back into the crinoid betting wicket! You're right that some crinoids could get pretty beefy. I'm still looking at the terminations of what seem to be crenullae, not septae. Until proven otherwise, I think I'll place my bet back with @ynot ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
doushantuo Posted July 8, 2017 Share Posted July 8, 2017 It kinda looks like both. I see no distinction in main and accessory septa*,and the "septal" structures sems very thick and equidimensional *edit:I might have ,where it not for the sediment filled interior The axial canal of crinoids can become filled with sediment,but that would have been a pretty big axial canal brauwechinod_diagen-pyrid-ossicles.pdf Link to comment Share on other sites More sharing options...
TqB Posted July 8, 2017 Share Posted July 8, 2017 I'm still with crinoid. As @ynot says, the inner curve is too crisp and parallel for a coral and it looks like a raised margin. The sediment doesn't necessarily reflect the width of the lumen, it's just filling a saucer shaped depression as in these: Tarquin Link to comment Share on other sites More sharing options...
abyssunder Posted July 8, 2017 Share Posted July 8, 2017 Some fossil crinoid pluricolumnals/columnals, those with very large lumen, tend to be crushed in the geological stress. (collapsed condition) I think that could be the case here. Below is an example (fig. 4a,b) of a Cyphostelechus claudus collapsed pluricolumnal which could be similar to the specimen in question in form and preservation status. " Stem obscurely heteromorphic, seemingly with noditaxes of 4 columnals, which are very gently convex in longitudinal profile and smooth-surfaced, sutures very finely crenulate, somewhat indented; articular facet with outer band of crenularium characterized by evenly disposed, straight crenulae in plane of facet and inner band with continuation of these crenulae bent abruptly downward from facetal plane into edge of lumen, which is relatively large and circular. (...) Discussion.-The fact that every specimen among many which have been collected is in a collapsed condition, evidently as result of the relatively large size of its axial canal, aids in easy recognition of the genus. (...) " Plate 14, figure *4a,b, facetal and side views of type specimen showing straight, even crenulae, very large collapsed axial canal (all observed specimens in this condition), and gently convex columnal latera, stem interpreted as weakly heteromorphic, with nodals (tallest columnals) lacking cirrus scars, noditaxes of 8 columnals, X5, x2.5. " 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...
doushantuo Posted July 9, 2017 Share Posted July 9, 2017 Abyssunder,while not necessarily disagreeing with you*,i think that ,from the standpoint of methodological rigour,a person shouldn't postulate flattening strain,at least not without corroborative evidence. * let's be clear about that We don't know the amount of overburden and the tectonic history of the area where the fossil was found(it would have to have been in situ too). Mechanical calcite twinning can lead to "free-face" dissolution of the calcite surrounding an initially "normal" lumen,through pressure solution. That might have widened it. Abyssunder's reasoning is thoroughly plausible Tarq,great pictorial support for the "Crinoid" viewpoint. Link to comment Share on other sites More sharing options...
.thumb.jpg.51c371f10936bbc883322324e44cc518.jpg)
Recommended Posts
Archived
This topic is now archived and is closed to further replies.