Sunny day in the La Salle Limestone

[deutscheben]

Yesterday I finally made it out to one of my favorite hunting spots after (almost exactly) a year away. This road cut in La Salle County Illinois had been visited earlier this year (I believe) by @Nimravis, @aek and @connorp,    but I really wanted a crack at it before summer fully kicked in. 
 

As I had been warned, it was already heavily overgrown, with poison ivy located intermittently across the slope. There were also mosquitoes in the shady areas and wasps in the sunny ones. However, with some delicate maneuvering I was able to avoid most of the hazards, with only some mosquito bites to show for it. 
 

I was at the site from 11:30 to 5:30 and the sun shone bright nearly the entire time, although thankfully an occasional breeze kicked up and cooled things off. 
 

Here is a sequence of the path up to the head wall, as you can see it quite brushy at the base of the cut.

 

 

 

 

 

All in all, I would call it a successful day. I was able to find quite a few interesting mollusks, both gastropod, cephalopod, and bivalve, that I had not encountered before from this site, and a few trilobite bits as well. The real reason I keep coming back to this location, however, is the high-quality and diverse chondrichthyan fauna found here, and it did not disappoint. 
 

In addition to many tiny shark bits which may or may not prove to be worth prepping, I found a few larger specimens which I am hoping are all or mostly complete.

 

The trip-maker was this beautiful Deltoptychius:

 

 

 

I also shared the site for part of the afternoon with @TheSandStorm, who was making his first visit to the locale- it was a pleasure meeting him. I love seeing new folks getting out to explore and discover the wonders of the fossil world! 
 

I will share more pictures of my finds in the next post. 

[deutscheben]

Oops, forgot to put in the post, this is the La Salle Limestone member of the Pennsylvanian Bond Formation.

 

Here are a couple overviews of everything I brought home:

 

 

 

This slim exposed edge will hopefully be a nearly complete petalodont crown of some sort- there is about 7 mm showing.

 

 

This minuscule Ctenoptychius is split between two chunks of rock, I’m not sure if I will be able to prep it back together. The part shown here is 5 mm wide.

 

 

Both exposed cusps of this cladodont tooth are broken, but I’m hopeful the remaining ones will be complete when I prep it. 9 mm is exposed currently.

 

 

In the field, the only visible part showing for this next tooth was this:

 

 

But with a little prep since I’ve been home, it has been exposed to be an excellent cladodont tooth, most likely Glikmanius. Unfortunately, the entire block it is in has a crack down the middle, so I will have to be careful. This tooth is 13 mm tall.

 

 

[deutscheben]

Here are some of my bivalve finds, I’m not even going to venture a guess on IDs at this point, so feel free to chime in!

 

 

 

 

And a few cephalopods:

 

 

[Nimravis]

Great post, I was going to head there today, but ended up going to the Kane County flea market with the wife. I might head out there tomorrow, but it looks like you cleaned the place out and the overgrowth is crazy. Last time I was out there, I placed some large blocks on those thorn bushes with the large thorns, hopefully they stayed down.

 

 

[connorp]

2 hours ago, deutscheben said:

Here are some of my bivalve finds, I’m not even going to venture a guess on IDs at this point, so feel free to chime in!

 

 

 

 

And a few cephalopods:

 

 

I’d be interested to see a couple more photos of the latter two bivalves, and the last cephalopod. The first bivalve seems to be the most common one there, the name is escaping me though. Starts with a ‘w’ I think.

[Ludwigia]

Looks like you've found some interesting stuff! At least you didn't have to deal with ticks.

[Tidgy's Dad]

Interesting report and some nice finds 

[Mart1980]

Nice overview and report of your fossil hunting dayGreat overview o

[deutscheben]

7 hours ago, connorp said:

I’d be interested to see a couple more photos of the latter two bivalves, and the last cephalopod. The first bivalve seems to be the most common one there, the name is escaping me though. Starts with a ‘w’ I think.

Thanks, perhaps Wilkingia? You spurred my memory and I compared it to a specimen @minnbuckeye was kind enough to send to me with that label and they seem quite similar. 
 

I also had some further thoughts on the first specimen I labeled a cephalopod- thanks to the extensive research and documentation of @cngodles, I realized this (and a few other specimens I have) is actually a sea pen-type bivalve, perhaps Aviculopinna? 
 

Here are some additional pics of those other bivalves, and a smaller specimen that I believe is the same type as the third one.

 

 

Edited June 5, 2022 by deutscheben

[deutscheben]

6 hours ago, Ludwigia said:

Looks like you've found some interesting stuff! At least you didn't have to deal with ticks.

 Thank you! Yes, that is one definite bonus for this site, I have never encountered a tick in 6 years of visits.

[deutscheben]

I spent some time prepping this morning and revealed the rest of the unknown petalodont specimen. Unfortunately, it’s only a partial crown, but an interesting one that I don’t have an ID for.

 

[connorp]

4 hours ago, deutscheben said:

Thanks, perhaps Wilkingia? You spurred my memory and I compared it to a specimen @minnbuckeye was kind enough to send to me with that label and they seem quite similar. 
 

I also had some further thoughts on the first specimen I labeled a cephalopod- thanks to the extensive research and documentation of @cngodles, I realized this (and a few other specimens I have) is actually a sea pen-type bivalve, perhaps Aviculopinna? 
 

 

I think I have a specimen like this one but with the shell preserved. I'll look later.

[aek]

Looks like a successful trip - that Deltoptychius is amazing. 

Edited June 6, 2022 by aek

[deutscheben]

53 minutes ago, aek said:

Looks like a successful trip - that Deltoptychius is amazing. 

Thanks! 

 

19 hours ago, connorp said:

I think I have a specimen like this one but with the shell preserved. I'll look later.

I also have one partial negative specimen that I believe is the same type with the shell- here is an overview and magnified section. Does that look similar to yours?

 

 

[cngodles]

On 6/4/2022 at 11:01 PM, deutscheben said:

And a few cephalopods:

 

 

Actually, this one looks like a pinnid to me. At least in this view. Example 1, Example 2

 

As for Aviculopinna, the usage for Pennsylvanian specimens should be "Aviculopinna" for now. Apparently it will be changing, and it will no longer be available for Pennsylvanian pinnids.

 

Here are some examples of the bivalve Wilkingia for comparison: Link <-- Plate, Link <-- Single specimen from the side.

 

 

 

Edited June 7, 2022 by cngodles

[deutscheben]

Thanks, @cngodles. For the first bivalve in my earlier post, it has some interesting detail on the outer shell:

 

 

While the inner steinkern has ridges more like those that seem typical for Wilkingia.

 

I was able to prep out a tiny crusher tooth last evening as well.

 

 

[jpc]

wow... look at all those cool Paleozoic teeth.  !!!

[fossilhunter21]

Those are some very awesome finds! I love Paleozoic teeth. 

 

Thank you for sharing,

 

-Micah

[deutscheben]

I was able to do some more prep on the nice Glikmanius from above. The good news is that I was able to largely separate the tooth from the 20 pound block of matrix, revealing that it appears to be nearly complete, including the root as well. The bad news is that the tooth is so fine and delicate ( I had to fix the small remaining block it is in with super glue or it would have split already) that it is beyond my capabilities to prep the rest of the way- I will look into sending it out to get prepped instead.

 

 

[jdp]

Acid prep might be an option 

[deutscheben]

Thanks @jdp. On the topic of prep, I finished the Deltoptychius above,  but unfortunately the block split through the edge of the tooth and I had to repair it (the front of the left ridge was affected):

 

 

 

I also popped a second coiled cephalopod from the matrix- it is very incomplete, but does preserve a few details that might be diagnostic: