jea Posted October 20, 2014 Share Posted October 20, 2014 I found this in the shallows yesterday while hiking around Lake Monroe south of Bloomington, Indiana. I've not had any luck so far finding a match online. I keep referring to as a corn cob because that's what it looks like to me (and, well, Indiana), but it would be helpful to know what it really is (if anything). I found a lot of crinoid stems/columns in the area as well, if that's of any assistance. I've included pictures of two sides and the base. Thank you for your help! Link to comment Share on other sites More sharing options...
morgansilk Posted October 20, 2014 Share Posted October 20, 2014 looks like coral structure (horn coral?) Link to comment Share on other sites More sharing options...
Wrangellian Posted October 21, 2014 Share Posted October 21, 2014 Looks like an agatized crinoid head. Interesting! Link to comment Share on other sites More sharing options...
tmaier Posted October 21, 2014 Share Posted October 21, 2014 The five-fold symmetry screams out "echinoderm" (such as crinoid), but I can't find anything that looks like it. Link to comment Share on other sites More sharing options...
Plantguy Posted October 22, 2014 Share Posted October 22, 2014 It's Neat whatever it is...I agree with the crowd on a crinoid something, especially since you are finding other crinoid material. At first glance I was thinking something more like a Calamites pith cast Artisia but I'm thinking otherwise now. I'm hoping one of the crinoid folks has a chance to see this and can tell us more and offer their insights. I used to pick up a bunch of crinoid stems in a stream bottom over in Louisville and as you can see and probably already know they have some pretty neat weathering effects---these are much smaller than yours but show some similar cross sectional/weathering patterns. Thanks for showing us! Regards, Chris Link to comment Share on other sites More sharing options...
kauffy Posted October 22, 2014 Share Posted October 22, 2014 It is a geodized Crinoid part (stem/calyx). I'm not sure of the processes during diagenesis which cause this but essentially they swell out with calcite growth in the center. I've found many of these, geodized calyxs and columnals in Indiana. "Turn the fear of the unknown into the excitment of possibility!"We dont stop playing because we grow old, we grow old because we stop playing. Link to comment Share on other sites More sharing options...
tmaier Posted October 22, 2014 Share Posted October 22, 2014 I've found many of these, geodized calyxs and columnals in Indiana. Do you have some photos of those? Link to comment Share on other sites More sharing options...
kauffy Posted October 23, 2014 Share Posted October 23, 2014 This from here http://www.mindat.org/forum.php?read,6,253403,page=4 "The accompanying pix show an unusual geode type found in Indiana and also in Kentucky and Illinois. They are geodized fossils. One theory of geode formation involves fossils decaying in the mud and their void being slowly replaced by a quartz rind and a central cavity. However these form, they are quite interesting and, in Indiana, found most commonly in Monroe, Washington and Lawrence counties. They are of gastropods, brachiopods, cephalopods, horn corals, crinoids and various shells. They range from several centimeters to many centimeters in size in some locations. The very best ones, as shown here, show remaining good fossil detail with parts of the original shell incorporated into the geode. Most are examples solid, but occasional examples are hollow with Quartz crystals as in an "ordinary or usual" quartz geode. For a hollow example, see my previous pix on page 2 of this thread with a smoky dew drop diamond variety. Enjoy..................BOB Edited 1 time(s). Last edit at 04/17/2012 09:29PM by BOB HARMAN." "Turn the fear of the unknown into the excitment of possibility!"We dont stop playing because we grow old, we grow old because we stop playing. Link to comment Share on other sites More sharing options...
kauffy Posted October 23, 2014 Share Posted October 23, 2014 Harry also touches on the processes involved in two gallery images: http://www.thefossilforum.com/index.php?/gallery/image/4601-brachiopod-geode/ http://www.thefossilforum.com/index.php?/gallery/image/4368-crinoid-columnals/ All in all I've found examples of crinoids, sponges, rugosa corals, gastropods that have been partially geodized... Mine are all in boxes otherwise I'd get some pics up! Hope that helps tmaier "Turn the fear of the unknown into the excitment of possibility!"We dont stop playing because we grow old, we grow old because we stop playing. Link to comment Share on other sites More sharing options...
Plantguy Posted October 23, 2014 Share Posted October 23, 2014 Jea neat find again! Bob, thanks for the ID info! Regards, Chris Link to comment Share on other sites More sharing options...
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