More Coprolite concentric layers?

[ilzho]

I am not sure where I found this, but it was on the east coast, probably North Carolina, just can't remember the exact location.

This has concentric layers, but I am not sure.

Thank you,

David

[abyssunder]

The successive layers remind me of a concretion formed in concentric growth.

[ynot]

Looks like a concretion to Me also.

Tony

[ilzho]

Sounds good to me....

I believe I'll take this out of my display case to make room for something else,  

[GeschWhat]

I have seen many coprolites with concentric rings, but only from the Triassic floodplain now part of the Bull Canyon Formation in New Mexico. The only way I was able to conclude they were coprolites is that I was able to examine over 1000 of them from the same location, some of which contained bone/scale inclusions. I am not sure why coprolites from that location formed the way they did...whether it was the fossilization process or the digestive features of the animal(s) themselves. The study of coprolites is really still in its infancy. 

 

I don't see any inclusions in your specimen. Without additional samples for comparison and/or chemical analysis, my guess is that it is that this likely a concretion.

[MarcoSr]

I had hundreds (donated them all) of Eocene marine coprolites from Virginia that had a scroll pattern from a scroll valve (certain species of sharks, rays and fish).  See the attached pictures of two complete specimens and the cross section of a third.  I've seen thousands of both spiral and scroll marine coprolites but never a marine coprolite with concentric circles.  I have hundreds of terrestrial Oligocene mammal coprolites from Nebraska.  None of them have concentric circles.  I also have a number of large reptile (croc) Paleocene coprolites from Maryland and none of those have concentric circles either.  So your specimen does not look like a coprolite to me.

 

 

 

 

Marco Sr.

[MarcoSr]

13 hours ago, GeschWhat said:

I have seen many coprolites with concentric rings, but only from the Triassic floodplain now part of the Bull Canyon Formation in New Mexico. The only way I was able to conclude they were coprolites is that I was able to examine over 1000 of them from the same location, some of which contained bone/scale inclusions. I am not sure why coprolites from that location formed the way they did...whether it was the fossilization process or the digestive features of the animal(s) themselves. The study of coprolites is really still in its infancy. 

 

I don't see any inclusions in your specimen. Without additional samples for comparison and/or chemical analysis, my guess is that it is that this likely a concretion.

 

Could you please post a few pictures of the coprolites with concentric circles?  I've never seen one with concentric circles before.

 

Marco Sr.

[GeschWhat]

4 minutes ago, MarcoSr said:

 

Could you please post a few pictures of the coprolites with concentric circles?  I've never seen one with concentric circles before.

 

Marco Sr.

I will try to photograph some tomorrow - both with and without inclusions. Nice coprolites by the way. The scroll valve specimens look very similar to some I have from the London Clay. Have you ever looked into what type of fish have scroll valves? It has been on my list of things to do.

[GeschWhat]

Here are some photos of a coprolite from the Bull Canyon Formation, Quay County, NM that has concentric rings on one end. I also scraped approx 2 mm off of the broken/exposed end with an x-acto blade. I had done this with one other coprolite this morning, but when I scraped the broken end, I found that the rings disappeared. I also scrapped off approx. 3 mm of the intact/rounded end and found no rings. You can see a fish scale in the center of that end.  This particular coprolite appears to have fractured in the center and was refused by mineral deposits. I hesitate to draw any conclusions from this quick little experiment, but for now I think the concentric rings in my samples were formed from exposure to the elements. 

[MarcoSr]

2 hours ago, GeschWhat said:

Here are some photos of a coprolite from the Bull Canyon Formation, Quay County, NM that has concentric rings on one end. I also scraped approx 2 mm off of the broken/exposed end with an x-acto blade. I had done this with one other coprolite this morning, but when I scraped the broken end, I found that the rings disappeared. I also scrapped off approx. 3 mm of the intact/rounded end and found no rings. You can see a fish scale in the center of that end.  This particular coprolite appears to have fractured in the center and was refused by mineral deposits. I hesitate to draw any conclusions from this quick little experiment, but for now I think the concentric rings in my samples were formed from exposure to the elements. 

 

Lori

 

Thank you for the pictures.  Really neat specimen.  Very interesting.

 

Marco Sr.