Hunting the Glen Dean Limestone

[FossilNerd]

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.  

 

 

Edited June 28, 2021 by FossilNerd

[piranha]

Kaskia chesterensis  is reported from the Glen Dean Fm of Kentucky and Indiana.

 

[Kane]

An excellent trip, Wayne! Although I am partial to the trilobite, those blastoids are very neat. 

Definitely a great assortment at that site. The cloth bag is a good idea on the steep slopes. Another option I used recently was to don a vest with tons of pockets (but I'm unsure if I'll roll up on myself if I tumble down the hill  ). 

[Fossildude19]

Thanks for the great report, Wayne!

Excellent finds and photos! 

Glad you were able to get out, and enjoy a bountiful harvest.  

Happy belated Father's Day and Birthday!   

[minnbuckeye]

Excellent, drool worthy finds!!! Your trip report has me fired up, as I leave tomorrow on a 2 day excursion. Did you see the crinoid calyx below the horn coral in this picture?

 

 

[FossilDAWG]

Really nice assortment of fossils.  I especially like the echinoderms but they are all sweet.

 

Don

[FossilNerd]

5 hours ago, piranha said:

Kaskia chesterensis  is reported from the Glen Dean Fm of Kentucky and Indiana.

 

Thanks Scott! It’s a bit of a bummer that I didn’t find something new and spectacular, but I’m glad to know what it is, and it’s still a great find for me. 
 

You wouldn’t happen to have a link to a paper you could pull out of your magic hat would you? I’d love to read up on them. 

[FossilNerd]

5 minutes ago, minnbuckeye said:

Excellent, drool worthy finds!!! Your trip report has me fired up, as I leave tomorrow on a 2 day excursion. Did you see the crinoid calyx below the horn coral in this picture?

Thanks Mike! 
You know, I don’t remember if I picked that up or not, and didn’t pay attention when I posted the report. 

 

Oh well… I’ll use it as an excuse to go back for another hunt soon.  

 

Good luck on your upcoming trip!  

[minnbuckeye]

I'll go fetch it for you.Just tell me exactly where to go!!!!

[FossilNerd]

6 minutes ago, minnbuckeye said:

I'll go fetch it for you.Just tell me exactly where to go!!!!

I’ll do you one better and take you there.  

 

Seriously, let me know if/when you will be in the area. I’d love to meet for a hunt, but even if my schedule won’t allow for it, I give good directions.  

[Myrmica]

One of the joys of this forum is to see how different the finds are in different parts of the world.  The blastoids, especially, seem very exotic from here.

[Jeffrey P]

Way to go  Wayne! Great Day! I love that site. Always stop there whenever I'm in Kentucky. Looks like you did even better than we did the last time back in September. The exquisite little brachiopod, the complete gastropods, the two last crinoid calyxes and arms, and the trilobite pygidium-totally awesome! Hopefully I'll be back sometime later this year. 

[grandpa]

Well, a very Happy Birthday to you, ol' man!!

What a great trip and great trip report.  Beautiful variety of great finds.  Congratulations.

[FossilNerd]

2 hours ago, Jeffrey P said:

Way to go  Wayne! Great Day! I love that site. Always stop there whenever I'm in Kentucky. Looks like you did even better than we did the last time back in September. The exquisite little brachiopod, the complete gastropods, the two last crinoid calyxes and arms, and the trilobite pygidium-totally awesome! Hopefully I'll be back sometime later this year. 

Thanks Jeff! I’m super happy with my finds and had a blast there. One of my favorite sites as well.  
 

Let me know when you are going to head this way and we will meet up again for more fossil fun. I had a great time last year!  

51 minutes ago, grandpa said:

Well, a very Happy Birthday to you, ol' man!!

What a great trip and great trip report.  Beautiful variety of great finds.  Congratulations.

Thanks Tom! I’ve got one more year till I’m “over the hill”. Unless there are fossils on the other side of the hill. Then I’m going early!  

[grandpa]

13 minutes ago, FossilNerd said:

I’ve got one more year till I’m “over the hill”

Well, by that logic I'm deep into the Valley of the Shadow of Death.

[RuMert]

Spectacular blastoids

[JimB88]

Awesome finds! Specially the blastoids! 

You and I need to collect together! I'll take you to the Fort Payne for some crinoid calyx goodness!

[Tidgy's Dad]

Belatedly :

A great report and photos Wayne. And some excellent finds. 

Love that trilo, quite rare if not new and the gastropods and echinoderms are marvelous. And the brachs of course. 

But I think my favourites are those beautiful little corals. 

 

Thanks for sharing.

[NickG]

OMG! These are amazing. Much better than what I was pulling out of the Bangor in northwestern Georgia or the Bluefield in southern West Virginia.

[FossilNerd]

On 7/2/2021 at 9:58 AM, JimB88 said:

Awesome finds! Specially the blastoids! 

You and I need to collect together! I'll take you to the Fort Payne for some crinoid calyx goodness!

Sounds fun to me. Tennessee isn’t that far away.  

[traveltip1]

Nice finds