Decorah rocks roadcut search

[Collector9658]

With my arm recovered and no work on the agenda, the urge to go out and look for fossils was irresistible today. Lots of rain here in Missouri lately has the rivers and creeks high, but that doesn't eliminate roadcuts if one is willing to search through overgrown rubble and walls of rock.

 

 The 2 hour drive to my site was fine, but unfortunately it wasn't going to be easy pickings today. The specific layer I wanted to look over was pretty overgrown.

 

The goal as usual, was to find a nice trilobite or two. Unfortunately, I didn't find any complete trilobites. Though, I still walked away with some nice fossils. Within my first couple minutes, I spotted something I've lately learned to recognize better, a conulariid!

 

Oddly, mosty of them I found at this location were fragile and pyritized like this next one. It is much easier to tell it is a conulariid with certain light refraction, which this photo lacks.

 

Quickly after finding these little treasures, I found a rock that appeared to have a section of nautiloid sticking out the end. I wacked it with another rock like a caveman would, and off popped a piece revealing a lovely crystallized nautiloid shell.

 

Wisely, I decided to do the next wack with my rock pick instead of another stone, which payed off and revealed the rest of the cephalopod shell. It is replaced with crystal, and I'm uncertain if I will be able to confidently ID it due to preservation. It is a real beauty, though.

 

Here it is after some washing.

 

Trilo-bits and brachiopods dominated the fallen rock I searched through. I did find a few nice brachiopods. Some weathered loose, some from splitting rock. The last brachiopod pictured is possibly the smallest brachiopod I have ever found, and was smaller than 1 millimeter in length.

 

Some gastropods were in place, weathering out of rock. I left them alone.

 

Finally, here are some trilobite parts. Lots and lots of pieces, from some different species.

 

This last one is probably just a pygidium, but I'll do some cleaning just in case to make sure it's not something like an enrolled specimen. I'll recount segments and wash it when I get home to confirm.

 

Alas, I had a great time out searching again, regardless of the high heat, humidity, and all the pests out right now. I lost a ton of sweat today, but boy does it bring me joy to be out again. The cephalopod find definitely made it worth the drive, thanks for reading!

Edited July 9 by Collector9658
Grammar

[minnbuckeye]

Nice finds! The Decorah Shale in your area must produce more trilobites than in my area. I wonder why the difference.

[Collector9658]

3 hours ago, minnbuckeye said:

Nice finds! The Decorah Shale in your area must produce more trilobites than in my area. I wonder why the difference.

Interesting observation. Where are you collecting most of your material from? This roadcut I've collected a few times now does have a lot of trilobite material compared to others I've searched close by.

[Jeffrey P]

Excellent finds- especially the conularids. It's been years since I found one of those. Big congratulations and thanks for posting them. 

[Neanderthal Shaman]

Nice brachiopods, I'm a sucker for good brachiopods

[MissouriBeginner]

I’m a beginner in northern Missouri. Thanks so much for posting these great pictures. You mentioned that you were looking in a specific layer. I recognise  that thick gray (shale?) layer in your picture and I never find any fossils in that. What layer are you looking in and how do you know what age it is from? Specific books/ websites about Missouri geology you could recommend? 
Sorry for all the questions just trying to learn. 
 

-Andrew 

[Collector9658]

On 7/10/2024 at 10:07 AM, MissouriBeginner said:

I’m a beginner in northern Missouri. Thanks so much for posting these great pictures. You mentioned that you were looking in a specific layer. I recognise  that thick gray (shale?) layer in your picture and I never find any fossils in that. What layer are you looking in and how do you know what age it is from? Specific books/ websites about Missouri geology you could recommend? 
Sorry for all the questions just trying to learn. 
 

-Andrew 

My best advice would be to first, familiarize yourself with the local geology around you. Missouri has an array of different ages of exposed rock, and dependent on where you are is what you'll find. Geologic and topographical maps of the county you are interested in can be nice tools to help determine were to look for fossils.

 

 I do a lot of reading as well, I don't have any specific links to give you but websites like https://share.mo.gov/nr/mgs/mgsdata/forms/allitems.aspx and https://www.jstor.org are very useful for seeking information. I would also recommend Roadside Geology of Missouri; by Charles G. Spencer as a useful beginner book.