Pink Fossils and Glass

[minnbuckeye]

Last Sunday, our rock club took part in Morrison, Iowa’s Pioneer Craft Fair, with a goal of educating the children in various topics of paleontology and mineralogy. I took the opportunity to discuss ancient sharks and show a variety of specimens that I have accumulated. Even the adults had a hard time grasping that  one of my display of teeth were actually from Iowa. The children then had the opportunity to split open some “rocks” revealing sharks teeth within. It was a hit and I enjoyed it more than the kids!!!!!!!!  

I did have the opportunity to explore a few fossil sites before the fair. My first stop was Bird Hill in Floyd County which is Cerro Gordo, Devonian. Brachiopods abound here. Hopefully, I can get a post of that hunt soon. The second location provided more Devonian finds but from the Solon Member, Cedar Valley Formation. My purpose was to collect some nice spirifers, Platyrachella iowensis. The wings of the spirifers are fragile so the specimens were left in the matrix for the trip home. Last night, while a few spirifers were extracted from a piece of matrix, I encountered two odd things. 

 

         Oddity #1 

                The brachiopods were mostly PINK!  The spirifers were not. What would cause this????????????  Preservation was obviously poor. 

 

 

 

Here is a piece of matrix where you can see where the spirifer was attached (The shiny white area). 

 

 

 Oddity #2 

           On the other side of the above pictured matrix, a root beer colored polished object was peeking out. A dremel was used to expose it more. I would say it looks manmade, but knowing it had spirifers next to it, I am without an explanation. It is for this reason that I ask for help. Actually, it reminds me of a piece of Green River Formation that I found containing  glass like scales of a gar. Could this also be gar? Any explanations for the unusual find would be appreciated, as this has me stumped and in need of an answer. 

 

 

 

 

 

 

 

 

 

 

 

 

 

  

The final picture shows there is structure in spite of the surface appearing smooth as glass. 

 

 

Edited September 22, 2021 by minnbuckeye

[tombk]

I’m curious to see whether anybody has a good explanation for this because I’m stumped. 

[Fossildude19]

Looks like a shark crusher tooth, to me. 

 

@jdp

[minnbuckeye]

The pictures posted do not show how glass like it is. I purposely took the toned down ones to post. It just seems too shiny compared to other Iowa teeth that I have collected. But tooth is a possibility, if not likelihood. If tooth, how could it maintain such a luster?

[connorp]

Yes it is a holocephalan tooth plate. From the pictures my first guess would be Psephodus. Here is Deltodus plate from the Pennsylvanian of Illinois showing similar luster.

Edited September 22, 2021 by connorp

[daves64]

@minnbuckeye maybe the pink ones are the girls dressed up in their Sunday best? 

[Rockwood]

1 hour ago, minnbuckeye said:

The brachiopods were all PINK!  The spirifers were not.

You noticed the internal conflict here ? Brachiopods ?

Perhaps @Tidgy's Dad can suggest a distinction that could cause that. Slight difference in shell makeup in some way, must be.

[minnbuckeye]

30 minutes ago, Rockwood said:

You noticed the internal conflict here ? Brachiopods ?

Perhaps @Tidgy's Dad can suggest a distinction that could cause that. Slight difference in shell makeup in some way, must be.

@Rockwood, I noticed it as I wrote but didn't make the adjustment. It has been altered slightly now. For everyone else, yes spirifers are brachiopods!!!

Edited September 22, 2021 by minnbuckeye

[Rockwood]

  Pedants in this neighborhood.

Perhaps it has something to do with the pores in the shells. Spirifers don't seem to have as obvious punctae as some others. Could it also be that one was transported containing a different 'filling' ? I think spirifers tend toward soft ground and current.

[jdp]

I don't think it's a tooth. I think you're looking at the enamel covering of a sarcopterygian dermal bone. Couldn't give you an ID on that little but my guess is probably lungfish.

[Rockwood]

19 minutes ago, jdp said:

enamel covering of a sarcopterygian dermal bone

Ah Ha ! I knew it existed. 

[minnbuckeye]

@jdp, Thanks for your fresh view on the specimen. I have collected many holocephalan teeth and none come close to the sheen on this fossil. So I am leaning towards your identification. Do you have photos of other specimens? My research finds mostly inaccessible articles. 

 

 @connorp, any thoughts about jdp's observation? I am still open to understanding this find. By the way, I have had 10 concretions open that contained ferns!!!! None were outstanding though. They appeared worn even though they were fresh cracked.

 

Edited September 23, 2021 by minnbuckeye

[connorp]

5 hours ago, minnbuckeye said:

@connorp, any thoughts about jdp's observation? I am still open to understanding this find. By the way, I have had 10 concretions open that contained ferns!!!! None were outstanding though. They appeared worn even though they were fresh cracked.

 

I'd take his opinion over mine.

Yes sometimes the preservation is just poor unfortunately. Perhaps due to mild decomposition before burial, or secondary weathering especially if you have a concretion portion and water was able to penetrate through an opening.