Cassandra Tiensivu Posted May 22, 2021 Share Posted May 22, 2021 (edited) Now, I have never seen one of these before. But… it feels like a crinoid piece of some sort. Only two of the rounded edges are visible, but I believe there are six sides to this. It reminds me of a connecting joint piece for a puzzle kit. Found it after cracking open this Coldwater Shale packstone from South Haven, Michigan. Edited May 22, 2021 by Cassandra Tiensivu Link to comment Share on other sites More sharing options...
Kane Posted May 22, 2021 Share Posted May 22, 2021 I'm not certain, but my thought leans toward possible arboral cup of a crinoid. 3 1 2 ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
Cassandra Tiensivu Posted May 22, 2021 Author Share Posted May 22, 2021 51 minutes ago, Kane said: I'm not certain, but my thought leans toward possible arboral cup of a crinoid. Thank you for your reply. I did look at a few of those online. They all seem to have holes in the center though, which this piece appears to lack? Link to comment Share on other sites More sharing options...
Kane Posted May 22, 2021 Share Posted May 22, 2021 The radiating striations is what put me in mind of that, so if not right at the "cup" area, maybe a theca plate. It looks very much like an echinoderm on the basis of the shape and the striations. I wish I could help with at least a genus, but I'm somewhat crinoid knowledge poor. I don't know the age of your rocks, so I haven't entirely ruled out rhombiferan (I tap out at the Devonian for anything non-trilobitic, and I assume these are Mississippian in age?). 1 ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
Cassandra Tiensivu Posted May 22, 2021 Author Share Posted May 22, 2021 I do believe it’s Mississippian, yes. What about a cirral grapnel? It’s still odd that mine has six sides. I’m not familiar at all with echinoderms, so we’re pretty even on that front. I have none in my collection, and haven’t even seen any in person. Wouldn’t they normally have long spindly legs? Link to comment Share on other sites More sharing options...
Kane Posted May 22, 2021 Share Posted May 22, 2021 Some do, but others like cystoids have platy theca. I have in mind those found in the Ordovician, like Pleurocystites: ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
Cassandra Tiensivu Posted May 22, 2021 Author Share Posted May 22, 2021 (edited) 27 minutes ago, Kane said: Some do, but others like cystoids have platy theca. I have in mind those found in the Ordovician, like Pleurocystites: Hmm. They don’t quite look complex enough to match my piece. It seems to me as though the six sides have rounded ends. You can see the outline of it with a bit of the curve if you look at the shadowing on the side that is not buried quite as deep in the host stone (more on the left side in the photos). It doesn’t quite feel right for a plate, with the spaces in between the rounded ends. At least, not a plate that has seams that meet up precisely. Edited May 22, 2021 by Cassandra Tiensivu Link to comment Share on other sites More sharing options...
Kane Posted May 22, 2021 Share Posted May 22, 2021 I see that, but I wonder if the sharper edge are buried under the overlying fossils and matrix, and that a bit of prep might reveal they are straight-edged. I'm honestly not sure! I did a dive into the UMMP database on the Coldwater Formation finds, but there was nothing. On a lark, and understanding he doesn't visit us as much, I am going to tag @crinus who knows Michigan fauna like no one's business. 1 1 ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
TqB Posted May 23, 2021 Share Posted May 23, 2021 Maybe Actinocrinites? This is a UK one but it does occur in the US. 3 2 Tarquin Link to comment Share on other sites More sharing options...
Cassandra Tiensivu Posted May 23, 2021 Author Share Posted May 23, 2021 Huh. Yeah, that looks very close. Time to go do a little research on that particular species. Thanks, TqB! 1 Link to comment Share on other sites More sharing options...
Cassandra Tiensivu Posted May 23, 2021 Author Share Posted May 23, 2021 1 hour ago, TqB said: Maybe Actinocrinites? This is a UK one but it does occur in the US. From everything I’ve come across for this species, it looks very close. But it still doesn’t quite match up. Maybe that is just because my piece isn’t worn down, unlike most of the specimens I’m coming across in my search. Does anyone know the frequency of appearances they’ve made in Michigan, perchance? Link to comment Share on other sites More sharing options...
TqB Posted May 23, 2021 Share Posted May 23, 2021 1 hour ago, Cassandra Tiensivu said: From everything I’ve come across for this species, it looks very close. But it still doesn’t quite match up. Maybe that is just because my piece isn’t worn down, unlike most of the specimens I’m coming across in my search. Does anyone know the frequency of appearances they’ve made in Michigan, perchance? Of course, there may be more than one species of Actinocrinites in the area (Actinocrinites being the genus), and maybe similar genera. 1 Tarquin Link to comment Share on other sites More sharing options...
JimB88 Posted May 23, 2021 Share Posted May 23, 2021 TqB is correct..its a plate from an Actinocrinites 2 2 Link to comment Share on other sites More sharing options...
pefty Posted May 23, 2021 Share Posted May 23, 2021 3 hours ago, TqB said: Maybe Actinocrinites? This is a UK one but it does occur in the US. Tarquin, I’m curious what species name was given in the caption for Figure 1c. 1 Link to comment Share on other sites More sharing options...
LisaL Posted May 23, 2021 Share Posted May 23, 2021 (edited) The names may be outdated, but here is Winchell's 1870 accounting of the species of Actinocrinus (Actinocrinites) in the Marshall and equivalent fauna (p. 384). I believe he considered the Coldwater Shale "kidney ores" and ironstone nodules to be part of the Waverly Group, along with the Marshall sandstone. https://www.jstor.org/stable/981492?seq=1#metadata_info_tab_contents Edited May 23, 2021 by LisaL 4 Link to comment Share on other sites More sharing options...
TqB Posted May 23, 2021 Share Posted May 23, 2021 1 hour ago, pefty said: Tarquin, I’m curious what species name was given in the caption for Figure 1c. It's A. triacontadactylus Miller, locality unknown, species range given as Visean which is long time. "British Palaeozoic Fossils", Natural History Museum - same in both a 1966 and 2012 edition which has revised names where they could find them. 1 1 Tarquin Link to comment Share on other sites More sharing options...
Kane Posted May 23, 2021 Share Posted May 23, 2021 Thanks, @TqB! I think you hit the nail on the head, and it slipped my mind in not tagging you! 1 ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
Cassandra Tiensivu Posted May 23, 2021 Author Share Posted May 23, 2021 1 hour ago, LisaL said: The names may be outdated, but here is Winchell's 1870 accounting of the species of Actinocrinus (Actinocrinites) in the Marshall and equivalent fauna (p. 384). I believe he considered the Coldwater Shale "kidney ores" and ironstone nodules to be part of the Waverly Group, along with the Marshall sandstone. https://www.jstor.org/stable/981492?seq=1#metadata_info_tab_contents From the text you linked, I found this paragraph. So there are (or were) seven or eight known species at the point this was written. None of them are marked as having been found anywhere in Michigan though. I think this is all of them: Actinocrinites Helice > pistilliformis > viminalis unicornis > pyriformis > pistillus Indianesis Coreyi Daphne (sp?) 1 Link to comment Share on other sites More sharing options...
TqB Posted May 23, 2021 Share Posted May 23, 2021 1 hour ago, Kane said: Thanks, @TqB! I think you hit the nail on the head, and it slipped my mind in not tagging you! Thanks, but I'm not generally well up on crinoids! This is a well known one over here though. Tarquin Link to comment Share on other sites More sharing options...
LisaL Posted May 23, 2021 Share Posted May 23, 2021 (edited) 3 hours ago, Cassandra Tiensivu said: From the text you linked, I found this paragraph. So there are (or were) seven or eight known species at the point this was written. None of them are marked as having been found anywhere in Michigan though. I think this is all of them: Actinocrinites Helice > pistilliformis > viminalis unicornis > pyriformis > pistillus Indianesis Coreyi Daphne (sp?) I know, it's maddening! I don't think there have been any real studies on fossils of the Coldwater shale, except for the 3-part lower Mississippian cephalopod study by Miller & Garner that's in Deep Blue. Winchell and Rominger have some notes on lower Mississippian fauna, and Lane & Cooper have a pretty big list of fauna from what they call the "Rock Falls, Cuyahoga series" and the "Lighthouse Zone," (which I think are respectively the lowest sections of the Marshall, roughly equivalent to or at least sharing much of the fauna of the Coldwater shale.) The other sections of the Marshall, the "Huron City zone" and the "Point aux Barques" zone, also seem to share some of the same fauna as the Coldwater shale. He mentions crinoid pieces and says there are "more than two species of Cyathocrinus," but that's the only genus I see listed. Their faunal list is in the section called "Fossils of the Marshall and Coldwater" near the end of this publication: https://www.michigan.gov/documents/deq/Vol_VII_Part2-3_307029_7.pdf I figure since there are no real crinoid studies or faunal lists for the Coldwater shale or Marshall sandstone, we'd have to look at genera described from beds of equivalent age. Equivalent rocks to the Coldwater shale/Marshall sandstone that I've heard of are the highlighted ones in this Kaskaskia sequence stratigraphy chart. The highlighted columns are early Mississippian equivalents of the Coldwater shale from the Iowa basin and the Ilinois basin. The columns moving to the left are more western formations in Nevada, Utah, and western Canada. The chart continues to the right of the Illinois basin with the Michigan basin and moves east and southeast to equivalent bedrock there, but my free preview of Regional Stratigraphy of North America didn't allow me to see those! Here's the Michigan basin equivalents. I don't think I've ever laid eyes on or thought about the Sunbury shale before! Maybe a lower Mississippian crinoid person will see this and recognize your crinoid! Or it might stay mysterious. I have seen some similarly-patterned plates just looking through literature on some of the equivalent formations! If I see any illustrations that stop me in my tracks, I'll post here. Tarquin's Actinocrinites is pretty close, I think! Edited May 23, 2021 by LisaL 1 Link to comment Share on other sites More sharing options...
piranha Posted May 23, 2021 Share Posted May 23, 2021 1 hour ago, LisaL said: The chart continues to the right of the Illinois basin with the Michigan basin and moves east and southeast to equivalent bedrock there, but my free preview of Regional Stratigraphy of North America didn't allow me to see those! Issue resolved.. Check your PM! Frazier, W.J., Schwimmer, D.R. 1987. Regional Stratigraphy of North America. Plenum Press, 719 pp. 1 Link to comment Share on other sites More sharing options...
LisaL Posted May 23, 2021 Share Posted May 23, 2021 (edited) 31 minutes ago, piranha said: Issue resolved.. Check your PM! Frazier, W.J., Schwimmer, D.R. 1987. Regional Stratigraphy of North America. Plenum Press, 719 pp. This makes me so happy, thank you!!! Looks like I was spreading my net too broadly, though -- the Coldwater's only really equivalent to the Choteau and Hampton of Illinois and Iowa, not the Burlington or Borden. And the Fort Payne formation of Georgia/Alabama looks promising! Edited May 23, 2021 by LisaL Link to comment Share on other sites More sharing options...
pefty Posted May 24, 2021 Share Posted May 24, 2021 Thanks Tarquin! The Cuyahoga is another close stratigraphic equivalent with a well-described crinoid fauna as well, though I don't see any species with similar ornament here: https://www.cambridge.org/core/journals/journal-of-paleontology/article/abs/camerate-and-disparid-crinoids-from-the-late-kinderhookian-meadville-shale-cuyahoga-formation-of-ohio/EEA4860C02923C4EAB678A89490C7087 1 Link to comment Share on other sites More sharing options...
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