Kansas City, Missouri – Fish/Amphibian spine, Shell ridge???

[Titan]

Hi Everyone,

I recently broke open a rock on my property and found this interesting fossil. I have tried to identify it but can’t find anything that looks similar. I know it's a long shot for an ID, but more knowledgeable thoughts on what it could be would be very much appreciated. It was found in Missouri, Jackson County, north of highway 350, south of highway I-70, east of 435, and west of 470. The rock was dug out when digging a basement and subsequently cracked apart and the fossil was within. Basement location is atop glaciated ridge.  

I am guessing (serious amateur here) that the rock would be somewhere in the Late Pennsylvanian Stage? The red circle in this map below is the approximate location it was found.

(http://www.kgs.ku.edu/Publications/Bulletins/83/07_up.html)

 

Here are the pictures…

 

 

 

 

Thanks in advance for any info!

 

[Pterygotus]

I can’t place it as I’m not familiar with the area but someone else probably can, some prep might help  

It’s definitely not a spine.

[connorp]

My immediate reaction was part of a cephalopod, ammonite maybe. @Missourian might have an idea, he is very familiar with the Kansas Pennsylvanian.

[Bullsnake]

Possibly a section of the nautiloid Tainoceras.

Nice find!

[Pterygotus]

I think that that would probably make the area Mesozoic. Enjoy your find! 
 

 

Edit: sorry, ignore my Mesozoic comment. Just did a bit of research and I’m wrong 

[Peat Burns]

Looks kind of like a crinoid calyx, although I can see that ammonoid looks right also.  

[Titan]

@Bullsnake thanks! And thanks for the suggestion! It does look a lot like other sections of Tainoceras out there. Most of the stuff I find around here I can fairly accurately ID, crinoids, clams, etc., but this one had me stumped because I kept seeing it as a spine. 

 

@Pterygotus Thanks! No worries, I kept seeing it as a spine despite my doubts. 

 

 

[Pbassham]

I see the crinoid part, but I guess I have fish on the brain.  I wanted to ask if you had pictures of the areas surrounding the disputed area.  I keep seeing fish patterns, fins, scales, etc. I might go outside and stare at the clouds for a moment to get it out of my system. I’m can’t wait to see what the final verdict is. It is a lovely piece, really interesting.

[Coco]

To call someone you have to put a @ with directly his/her name : @Bullsnake and @Pterygotus (they will receive a notice).

 

Coco

[Spoons]

My first reaction is that what you have exposed there is the outermost whorl of an ammonite.

 

Others have diagnosed it as a Tainoceras  Nautaloid, so I’d have to be inclined to agree.

[Spoons]

Tainoceras section from Dallas Paleontological Society

[Spoons]

Upon further investigation I would like to contract my endorsement of the specimen’s diagnosis as Tainoceras. 
 

Instead I propose an identification as Metacoceras. Reference picture attached. The reason I feel I must reject this diagnosis is because the processes on the shell of Tainoceras are to pronounced and too few in number to be a good match in my opinion. Tainoceras also exhibits an extremely distinct ribbed pattern on the back of the shell. Instead, I suggest that Metacoceras is a much better match due to similarities in process morphology and frequency of processes on the ridge of the shell.
 

Link to Pictoral Guide to Upper Pennsylvanian Cephalopod fossils by Ben Neumen, courtesy Dallas Paleontological Society: 

[Titan]

@Spoons I agree 100%. Metacoceras seems much more likely of a fit. Thanks for the info!

 

@Pbassham Sure, here's just a rough description from my observation. The site is on a ridge, the top of the ridge has a layer of yellowish brown rock that flakes and breaks apart easily which contains numerous invertebrate fossils. Below that it turns into a hard gray rock that is very hard to do anything to. We have a lot of these rocks around our house and property and I've seen them being dug out of the ground when making ponds or basements* from the neighbors along our ridge. They usually have a bunch of shell fossils/crinoids in them, but I've not seen anything quite like the one I posted. There was a farm here back in the late 1800’s early 1900’s that had a well/cistern and they used the weak yellow rocks to build a retaining wall (pic #4 and #7) as well as the walls for the well/cistern that has since been filled in.

 

Here's a bombardment of pictures for you. 

 

#1 the ridge

 

#2 the ridge at the top

 

#3 Crinoid from the rock in picture #2:

 

#4: Rocks pulled out from top layer and used for retaining wall. They are roughly 10 ft. long by 4 ft wide and 8-12 inches thick. 

 

#5: Crinoid from rock in picture #4. 

 

#6 Crinoid from rock in picture #4

 

#7 rock wall 

 

 

#8 Unknown fossil from same rock as the original post. 

 

*One could argue that here in KC they are the same thing >.<

[Missourian]

I agree with Metacoceras. It is the most common coiled cephalopod in the KC area. Tainoceras is present, but is much less common. Besides, your specimen has only two rows of bumps instead of four, which would peg it as Tainoceras.

 

The rock most likely came from the upper Winterset Limestone. This unit can be quite prolific fossil-wise, though it can be hit or miss. The texture of the rock ridge in pic #1 resembles the Bethany Falls Limestone, which underlies the Winterset.