Mississippian Fish Teeth #1

[minnbuckeye]

          Every year, I take some time out to collect the Burlington Formation (Mississippian) of SE Iowa. It is about 70 ft thick in the area I hunt and the limestone is a coarse-grained rock made up mostly of crinoidal debris. Usually, my goal when visiting is to find nice examples of crinoids and brachiopods. But lately, I have taken interest in the primitive shark teeth that exist in the upper few feet of the Cedar Fork Member of the Burlington. So late summer, I threw five 25 lb rocks containing evidence of Chondrichthyan teeth into the back of my pickup to process this winter. Here is an example of a rocks I have yet to process. Notice the black specks on the surface. This is what shark material looks like.

 

 

Most surface teeth are worn and not worth collecting. The pristine teeth are inside. So, the next step is to break the large rock into smaller pieces in hopes to find a keeper. I use a vice to break off pieces. If a hammer is used instead, the vibrations destroy many of the fragile specimens. Every small black specks must be explored to see if they are the tip of a nice tooth.  90% of the specks are nothing but fragments. But every tenth one makes investigation worthwhile! 

 

Junk:

 

 

Junk:

 

Success!!!

 

     So as not to overwhelm everyone, I am going to show my finds in a few different posts. Images of Burlington fish on line is marginal at best. Consequently I will provide more examples than I normally would. Here are a few teasers for today.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Edited February 22, 2022 by minnbuckeye

[Fossildude19]

I can only assume you found this dissertation?

Great finds, and neat stuff to explore!

[Plax]

I'd experiment with acid on this. A bad one first of course. Neat material.

[jpc]

I had good luck with the ones you sent me a few years back.  Like you said, mostly scraps, but a few decent specimens; none as nice as your cladodus, though. .  I used a #3 microjack under the microscope.  

[jpc]

33 minutes ago, Fossildude19 said:

I can only assume you found this dissertation?

Great finds, and neat stuff to explore!

Thanks for this, Tim.  Looks like acetic acid is the way to go.  This guy got some great specimens using acetic and/or formic acids.  

 

[minnbuckeye]

@Fossildude19, yes I am making most of my "IDs" based on this publication by our very own forum member!! In fact, my crinoid is featured in it!!!!!

 

 

@Plax, Actually, I do have some samples in acid as we speak! But to dissolve a 25 pound rock takes too much acid. LOL

 

@jpc, If you would like a piece of the rock pictured, let me know.

[Plax]

Yeah; I was suggesting one of your broken off chunks. White vinegar is cheap by the gallon. Good luck!

[deutscheben]

Neat, so many bits! I look forward to seeing more of your finds, the Burlington is such an iconic midwestern formation.