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I've heard recently that the Glen Dean Formation (Carboniferous) outcrops in Illinois are very fossil rich, especially with Invertebrates. However, I haven't heard much about vertebrate fossils coming from that formation. https://igws.indiana.edu/IGNIS/GeoNamesDetails.cfm?ID=805C6AF7-75E2-40C8-A8D2-C7535D35F7C8 Hoenig MMJ - MS Thesis - Chondrichthyan Diversity (Updated) (1).pdf Does anyone know what kind of vertebrate fauna (mainly fish) fossils are found at the Illinois outcrops of the Glen Dean Formation and if it's connected to the Burlington-Keokuk Fish Beds?

Found a real nice exposure of the Glen Dean Formation in central Kentucky recently. Oh man did it not dissapoint. So here is some of the best crinoid material I have ever found. A calyx with partial arms, pictured with some stems and ossicles. A single ossicle, with crinoid spins, that are still sharp. Both of which are as common as gravel here. A small peculiarcalyx and crinoid cup. This massive gorgeous Pentremites sp. I found this one on my first trip, so unfortunately no scale but I will upload more of it later. More large blastoids this time around as well. It may not be as diverse, but I have only seen this quality of blastoids in the Thunder Bay of Michigan. An uncrushed Composita sp. A nice spirifid of some variety. I want to say Neospirifir but that is likely incorrect as it does not fit the range. The partial pygidium of a Kaskia chesterensis? Mm mm mm! These delicously preserved Zaphrentis spinulosum. I have some monsters of these, but again they're from a previous trip so I will post them later. I did find some gastropods and tons upon tons of crinoid stems and bryozoans as well, here is one image of them with various other pieces. The Glen Dean of Illinois occurs nearly on the same Latitude as this locality does. However it does not compare with the sheer quality and quantity to be found here in Kentucky.

Found these yesterday. Getting them out of the rock was a job. I was wore out afterward. https://imgur.com/a/wWGIEst I believe they are Phanocrinus.

As a late Father's Day gift and early Birthday present (I turn 39 tomorrow ) I spent 4 hours Saturday morning in the Glen Dean Limestone. A Carboniferous (Mississippian) formation. As usual, I was channeling my inner mountain goat and scrambling around a Central Kentucky roadcut. As I pulled up to the road cut my heart sank. Grass had grown on the exposure. If memory serves, the last time I was here was in the middle of September of last year and the exposure was bare. Most finds are small so I was worried that I wouldn't be able to find much. Luckily my fear and apprehension was unfounded. As a side note... I wasn't intending to use a screw driver for scale, but you will see the tip of one in multiple pictures. I was using it as a way to mark where the fossil was while digging my phone out of my pocket, but since it is there I will tell you that it is 5mm wide to give a little perspective. With the finds being on the small side, and surface collecting the norm, these were my weapons of choice. A collecting bag of some sort is preferred here over my usual plastic container. It's been my experience that the bag conforms to the slope better and tends to roll up on itself should it start to tumble down the hill side preventing its contents from spilling out. Below is a typical section of ground here. It is littered with bryozoan and crinoid stem fragments. I knew the day was going to be good when my first find was this very long example of Archimedes sp. I'd estimate it to be about 7 inches (nearly 18cm) long. In an exposure that is notorious for broken and flattened fossils, this was a real treat. Unfortunately it was in a rock that was too thick and wide to chisel it out of. I'm fairly certain my chisel and hammer would have worn out long before the rock did. Horn coral are always nice to find. Especially these, which are some of my favorite. Zaphretites spinulosum. Another favorite find from this exposure is crinoid cups. There are multiple species of crinoid here. Crinoid calyx cups are on the uncommon to rare side of finds, but I made out like a champ with crinoids on this trip. Stick around to see some of my rarer finds of the day. Echinoderms are probably my favorite type of fossil to find, and so crinoid cups are great, but my absolute favorite thing to find here is blastoids. Pentremites is the genus to be found. There are several species known from the Glen Dean. That is it for the field pictures. Next up are a few pictures of finds taken after I got home. Horn coral (Zaphretites spinulosum) Calyx cups from various species of crinoid. Blastoids! All are species of Pentremites. The ones on the left are massive for the formation, and rare. Although they are preserved in the typical fashion, crushed and deflated. The middle are more common and are typical size and preservation. The ones on the right are typical size, but are inflated. Pardon the fingers, but it was the best way I could find to get a clear picture of this particular blastoid. I wanted to show the preservation detail. Lovely. Extra long crinoid stems that I grabbed. An line up of brachiopods found here. The last three on the right are typical of the preservation. Just like anything else here they are deflated and crushed. The middle two are new to me species and were found at the transition layer from shale to limestone. The three on the left are preserved in a rare fashion being that they are inflated. Close ups to follow. Again, pardon the man hands. And finally these next few pictures are of the rarest of my finds from this formation to date. These are small gastropods. I still need to research an ID, but @Jeffrey P told me about these when we hunted the location last year and mentioned them as being very rare for the exposure. We only found a couple of broken fragments between the two of us after hunting for 6 hours or so. I found 5 complete ones this time around. Next up is a crinoid cup that has plates attached. I also found a grouping of crinoid arms. These do not go together and were found far apart. Not quite a complete calyx, but maybe next time. That concludes my report. It was a good turn around to a slow fossil year for me. I added many new and rare (for this exposure) things to the collection. I couldn't have asked for a better Father's Day/early Birthday present! Thanks for looking. Edit: I almost forgot the rarest of the rare! I have never read about trilobites being described from this formation and have never seen any other than this tiny pygidium. A small (4mm), but extremely rare (and possibly undescribed) find.