Rockaholic Posted February 1, 2013 Share Posted February 1, 2013 Last summer I spent some time collecting fossils at a Mississippian mudstone deposit in a creek bed in southern Indiana. Imbedded in the mudstone were a lot of silicified crinoid fragments sandwiched in between layers of bryazoans.This is a sample of one of the bryozoans. Two questions can any more detailed description of this bryozoan be made and is the “stem” that the arrow is pointing at part of the anatomy of the bryozoan or is it a crinoid fragment? Link to comment Share on other sites More sharing options...
the tatter Posted February 1, 2013 Share Posted February 1, 2013 Looks like crinoid stem sections to me, but wait for the experts to be sure. Nice bryozoan fan. Discovery consists of seeing what everybody has seen, and thinking what nobody has thought. Albert Szent-Gyorgyi Link to comment Share on other sites More sharing options...
mikeymig Posted February 1, 2013 Share Posted February 1, 2013 Pretty cool! The bryozoan grew on the crinoid stem and was preserved as it lived. A great display piece. Mikey Many times I've wondered how much there is to know. led zeppelin Link to comment Share on other sites More sharing options...
Rockaholic Posted February 1, 2013 Author Share Posted February 1, 2013 Interesting. I had'nt thought of the crinoid stem being the platform for the bryzoan colony to grow. Link to comment Share on other sites More sharing options...
Malcolmt Posted February 1, 2013 Share Posted February 1, 2013 (edited) At Arkona where I collect somethimes you often find bryozoans and gastropods in association with crinoid stem sections. One of the markers people look for when finding crinoid layers is the presence of gastropods. Unfortunately I have never been lucky enough to find a complete crinoid there. Edited February 1, 2013 by Malcolmt Link to comment Share on other sites More sharing options...
JimB88 Posted February 1, 2013 Share Posted February 1, 2013 (edited) umm, actually thats the fenestrate fan of Archimedes - the center has worn away leaving the fan. There was a fan on each of its whorls. I need a close up of the stem area to see if it goes with it or not. Edited February 1, 2013 by JimB88 Link to comment Share on other sites More sharing options...
erose Posted February 1, 2013 Share Posted February 1, 2013 Different fenestrate bryozoans will have different patterns of the little zooaciums(sp?) Some will have these openings only on the stems while others will have them on the cross bars as well. Some will be lined up very neatly in one, two or more rows while others might appear more random. Some will have a keel down the middle of each branch. And the spacing, orientation and shape of the cross bars will be different. And of course the overall sizes can vary. Link to comment Share on other sites More sharing options...
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