Ridenhower Formation scavenger hunt 8/1/23

[Collector9658]

Curious and a bit crazy, I drove a couple hours out to what used to be a popular blastoid collecting site in Illinois. I've read online that this location has been the example of a couple bad apples ruining the bunch in the past, so I wasn't sure if I could collect or not. The exposure lies in a creek between private property, so to cover my bases I went knocking on some doors. Sometimes, that's all it takes. I spoke with the landowner, and he was nice and did not mind me looking and collecting.

I would kindly express that anyone else with similar intentions do the same.

Excited, I raced down to the exposure. A short walk from my car and I found the creek. The post will be picture heavy.

A bit overgrown, but that's normal during the summertime in the Midwestern USA. I waded to the other side of the creek and started checking the mud towards the bottom. It didn't take long until I found a Pentremites blastoid! It was a decent size, though a bit compressed. Checking back, I noticed another one right below it, and gave them a quick creek wash.

I then went up and started checking the first lower wall and noticed a nice dirty blastoid eroding out of what looks like a mudstone/ shale rock.

I decided getting low on my hands and knees and checking through all the eroded material would be the best approach. This worked well. There were many blastoids just waiting to be plucked at the surface, or waiting just below some debree.

So far, they were all in nice condition. The soft matrix attached also comes off easily in most cases. After finding 4, I got overwhelmed a bit from excitement and had to sit for a few minutes. A short break later, I started looking again and found more. A lot more.

There were so many Pentremite blastoids just littered around. It was almost like picking up pecans when they start to fall, but better! 

Venturing towards the top of the exposure, I noticed some larger examples. Some were exposed in the soft wall, while a few looked like they had fell out recently.

Here was a very nice specimen I found towards the top buried in mud.

After a quick wash

Almost everything I had found was just laying there and weathered out. No tools were required. I flipped through and looked at some of the bigger chunks of rock, but most were barren besides one cool little multi block.

There were also some nice brachiopods and bryozoa I collected, which I sadly didn't photograph. I did find some sort of crusher toothplate as well.

I think the blastoids always get most of the attention here, and I can understand why. I've never collected a spot with them so abundant.

My final find ended up being my favorite, and biggest blastoid.

I'm amazed at the quality, sizes, and sheer abundance of Pentremites blastoids that are here.

This was a lot of fun and is a productive place to spend a day.

Edited August 2, 2023 by Collector9658

[Fossildude19]

Great finds and report!

Thanks for posting it here.  

[FossilDAWG]

Nice report.  You did well! I stopped by there a few years ago.  It was November and pretty cold as I recall, especially when I unintentionally got my feet wet fording the creek.  I didn't do as well as you, but I found a few decent blastoids, enough to keep me happy.

 

Don

[jpc]

Thanks for taking us along.  I feel like I found my very own blastoids.  

 

[Jeffrey P]

Very nice report and excellent specimens. Congratulations. Getting the owner's permission to collect really paid off. 

[Denis Arcand]

Nice pictures, and specimens  

[Tidgy's Dad]

Beautiful. 

[jforbes]

Thanks for the post and nice report! I have considered making the trip myself but have been hesitant to drive what would be around two hours to get turned down/not find the property owner. Blastoids are such a fun fossil to collect.

[sixgill pete]

Wonderful. Thanks for sharing these with us.

[digit]

Glad to see that that site has recovered. The story I had heard was that the bad apples decided to harvest the site with a pressure washer to quickly erode out large amounts of the fossil bearing material which caused the overburden to slump down covering up the interesting formation making it inaccessible. Possibly, that overburden has now eroded away. Glad you were able to locate the correct land owner and secure permission. I have a strange fascination with the geometrically beautiful blastoids and this site was at the top of my list before being crossed off as "gone". I may have to add this back to my wish list and consider a roadtrip again sometime.

 

 

Cheers.

 

-Ken