Which Paleozoic Period?

[Odd Rocks]

These were found in a layer of broken-up pieces in matrix support on top of the Ohio Valley Knobs (~900’ elev).   The Falls of the Ohio are 400’ elevation and there are no exposed rock layers at the site where these were found.  There are no pieces larger than the crinoid at 11:00, and nothing intact larger than a tennis ball.

It took me 5 years to finally peg these as Paleozoic fossils.  I started picking up the round rocks thinking they might be agates, but very few of the pieces I opened up had any crystals, much less agate.  Some of the broken pieces suggested a solid interior, and the rock is very hard in some of them and it polishes to a mirror-like reflectivity.  I initially dismissed the idea of fossils because all of the fossil beds were 500’ below, so I kept looking around at minerals for identification.  I even spent some time researching asteroid ejecta and tectites.  It was only after I solved the “broken pieces” riddle that I came back to fossils.  
 

I had also started picking up pieces that looked fossilized even if they were not round.  I soon realized the ground was literally littered with these broken pieces and that they seemed to be coming out of the hillside as a layer, not really distinct because of all the matrix support, but you can visualize it standing back from the area.  Then I came across the Silurian Sea and how glaciation later scraped across that limestone layer the sea left behind.  I think I saw it on an interpretive display somewhere.  If glaciers scraped up a bunch of fossils in those old sea beds, they’d grind ‘em up and spit ‘em out at the southern terminus.  This happened more than once during the Last Glacial Period and of course the Ohio River Valley demarcates much of that southern terminus.

 My working theory is this is a layer of glacial till left over from the Last Glacial Maximum, or perhaps even the Penultimate Glacial Period as this site is outside the established LGM boundaries.  Can anyone help me place them within the Paleozoic era based on their morphology?   I can post detailed even magnified pics of any piece.

Here’s a link to a short video moving around the table: 

 

[Fossildude19]

Sorry, but I am not seeing any specific fossils here, only concretions.

[ynot]

Hard too tell from one bad picture what these are, could be concretions or agate nodules or some of each.

Need close ups of a few of the "best" pieces.

[Rockwood]

I'm afraid that dating layers of glacial material may be a lost cause. As pointed out above, you would be better off to focus on what you think look the most like fossils individually.  

[Samurai]

19 minutes ago, Rockwood said:

I'm afraid that dating layers of glacial material may be a lost cause. As pointed out above, you would be better off to focus on what you think look the most like fossils individually.  

I would have to Echo Rockwood's statement. Glacial deposits can transport things Very far away from origin.

For example I have seen Cretaceous fossils aged (85~66MYA) in Northwest Missouri's glacial till despite the youngest rocks in the region being Pennsylvanian in age (300 Million years old.) In the same sediment there was granite from who knows how long ago. 

 

The only reason why I knew the fossils were cretaceous was due to the Ammonites Suture patterns and accidentally finding out its genus. For crinoid fossils/rocks its almost impossible. 

Edited June 24 by Samurai

[Odd Rocks]

Better pics of individual pieces, no problem but I’m still learning how to light and shoot pieces.  I’ve tumbled a couple dozen pieces, definitely not agate or simple concretizations, they wore down too fast and each one left something small and hard behind.  I’ll have those ready soon,.

 

I think the “concretions” are actually fossils themselves, or they contain fossils. Of those, some of the fossils are obvious from the outside, others I only know about because of broken pieces.  I’ll post best examples of all three.

 

Some of these are “heads” with evidence of a stalk and some just “heads”:

 

 

[Odd Rocks]

These have fossils embedded inside, either seen suspended in a matrix or on a broken surface:

 

[Rockwood]

One of these is tabulate coral and one is rugose coral. 

[Odd Rocks]

So basically I’ll never be able to place any of these fossils within the Pleistocene because they are in glacial till which gives no clues about the age of the parent rock, correct?  They are before the Permian-Triassic Extinction and after the Proterozoic era ended, the Triassic, but that’s the best I can hope for?  I’m not complaining, just asking.  I was hoping morphology would be more definitive, but I also understand that the specimens at this site were chewed up and transported by a glacier so they’re not in the best condition.  For now, I’ll make do with learning my Paleozoic phyla and genuses by posting individual specimens.

 

I am curious, however, if this site is something worth “reporting”.  This site and another I found about 20 miles south are clearly outside published maps of how far the ice sheets extended during the LGM.  This is glacial till on top of the Ohio Valley Knobs containing busted-up fossils usually found in layers 400’ below.    IU-South and University of Louisville are nearby, or should I contact the Indiana or Kentucky state geological departments.

Indiana Glacial Map.pdf

[Rockwood]

Yes. These are corals that went extinct in the end Permian extinction event. Sometimes experts can determine the age more precisely from morphology, but I can't from these photos. The LGM is only the last glacial maximum. Other glaciations and glacial outwash have to be considered to explain the present location. A lot can happen in 250 million years. 

[Odd Rocks]

There is some evidence of glaciation from the PGP located about 90 miles west by southwest from this site and at a lower elevation.  No reason to think these couldn’t be from the PGP, or maybe even an earlier glaciation, though it’s my understanding that North America was in a different place during previous glacial periods.   The layer these are coming out of is not at the very top of the Knobs, so it was buried fairly long ago I think.

 

Sounds like I need to consult a local expert.  Maybe there’s a way to date where the till is from or how long ago it was deposited by analyzing the support matrix, or the degree of oxidation on the broken surfaces.

[Rockwood]

Yes. Ask a local sounds like a plan. 

[Mark Kmiecik]

Glaciers in the mid-US extended as far south as the Missouri and Ohio river vallies, so where these were found is already on record as an area with pockets of glacial deposition.