Coprolite or Tilly Bone?

[GeschWhat]

I've bought this as a coprolite a long time ago. I don't have an exact location, but the person I bought it from dives costal rivers in the Southeast United States. Something about this one always seemed a little weird. As I have been re-photographing my coprolites, I discovered one specimen in my collection that was actually a tilly bone. It had been mounted in a plastic display case, so I had never looked at the bottom. The composition of this seems similar to that specimen. But I do have true coprolites that also have that surface texture. I know at one time I thought this might be a cololite or a steinkern of some sort, but that didn't seem quite right either. What do you all think? The bottom view is the one that I thought might be diagnostic. Thanks for looking!

 

 

 

 

[GeschWhat]

Here are the end views:

[Darktooth]

What were the results of the lick test, Lori?

[daves64]

2 hours ago, Darktooth said:

What were the results of the lick test, Lori?

Could that be why it's so shiny? 

[GeschWhat]

 

2 hours ago, Darktooth said:

What were the results of the lick test, Lori?

15 minutes ago, daves64 said:

Could that be why it's so shiny? 

How did you know? My dad always told me there is nothing better than a good spit polish.  Actually, the shiny east coast copros don't usually stick. 

[GeschWhat]

Here is another view of the funky side.

 

 

[GeschWhat]

@Carl, @MarcoSr, thoughts?

[daves64]

@GeschWhat Maybe it's a tilly bone that got gobbled up by a fish, passed through and got expelled... making it both a tilly bone and  a coprolite.. 

[GeschWhat]

It would be so cool to find a tilly bone in poop! I do like your thinking. 

[Rockwood]

Looks like it, is just a coprolite to me.

[MarcoSr]

6 hours ago, GeschWhat said:

@Carl, @MarcoSr, thoughts?

 

Lori

 

Your specimen doesn't look like a tilly bone to me.  I see two features that suggest a shark scroll coprolite.  The first is what looks like the end of the scroll wrapping in your picture below.  You can see this end of the scroll wrapping in my picture.  Also scroll coprolites have an indentation on at least one end which you can see in the last picture.

 

 

 

 

 

 

Marco Sr.

[GeschWhat]

Thanks, @MarcoSr! That makes me feel better. I had this one on my website for years as a fish coprolite (but not a scroll). I got nervous when I discovered this tilly bone among my coprolites. Also, few weeks ago I was helping someone identify coprolites, three of which were very large tilly bones. I had never even heard of tilly bones before joining the forum. 

 

By the way, the paper on your Nanjemoy coprolites is fantastic!

 

 

 

 

[sharkdoctor]

Hi Lori,

I agree with @MarcoSr.Definitely a coprolite. These sorts of scrolled coprolites are ubiquitous in some underwater exposures in east coast rivers. The odd shape on this one is likely due to a combination of flaking of some of the scroll as well as water wear. Also, yours seems to have a possible bite or scrape mark. I really love these for a variety of reasons. Pieces like this are frequently found from lag layers. They've been beaten up a bit and waterworn, which can often reveal surface detail that would be hard to see if the piece was found intact from its original place of deposition. The wear and tear that they often show allows you to see the structure of the coprolite, as well as revealing interactions with the environment (including bite marks, scrape marks and structural collapse).

 

The material that the piece is made out of is also very indicative of a coprolite from a lag layer. These are staple of my coprolite collection and I never cease to be amazed at how much some of these reworked coprolites look (and feel) like resin or plastic. Below is a tray of coprolites from an east coast trip this summer that might make for an interesting comparison. You'll notice some have the same waxy finish. There are some pseudo-coprolites thrown in just to keep things interesting 

 

 

-Aaron

 

 

 

[Carl]

On 10/22/2020 at 12:21 AM, GeschWhat said:

@Carl, @MarcoSr, thoughts?

I agree with @MarcoSr and @sharkdoctor on every point.

[GeschWhat]

On 10/22/2020 at 10:56 AM, sharkdoctor said:

Hi Lori,

I agree with @MarcoSr.Definitely a coprolite. These sorts of scrolled coprolites are ubiquitous in some underwater exposures in east coast rivers. The odd shape on this one is likely due to a combination of flaking of some of the scroll as well as water wear. Also, yours seems to have a possible bite or scrape mark. I really love these for a variety of reasons. Pieces like this are frequently found from lag layers. They've been beaten up a bit and waterworn, which can often reveal surface detail that would be hard to see if the piece was found intact from its original place of deposition. The wear and tear that they often show allows you to see the structure of the coprolite, as well as revealing interactions with the environment (including bite marks, scrape marks and structural collapse).

 

The material that the piece is made out of is also very indicative of a coprolite from a lag layer. These are staple of my coprolite collection and I never cease to be amazed at how much some of these reworked coprolites look (and feel) like resin or plastic. Below is a tray of coprolites from an east coast trip this summer that might make for an interesting comparison. You'll notice some have the same waxy finish. There are some pseudo-coprolites thrown in just to keep things interesting 

 

 

-Aaron

 

 

 

Thanks, Aaron! I am officially jealous. It has been years since I have been coprolite hunting - or should I say in an area that has them.  Is that an inclusion I see on the far right, second from the bottom? Did you dive for those? 

 

I was kind of iffy on feeding trace, although it does look like it in the photos. I just peeked at them again it under the microscope and am still not really sure. If those are tooth scrape marks, the grooves filled in on themselves a little before it fossilized. There is such a weird texture in that area, it is hard to tell for sure. Maybe I'll make a silicone mold to see if it makes things any clearer.

[sharkdoctor]

This batch was from underwater, but the layer that produces them has many exposures in outcrop throughout Maryland and Virginia. If you ever make it down this way, it would be fun to collect some of those exposures together. The layer produces a staggering array of morphotypes. It is a copro-fauna that is begging to be published.

 

Those traces look very much like some that have been cropping up in the lowest part of the Calvert Formation. They are always straight and have three to 5 parallel lines. They range from very distinct and sharp to marks that clearly experienced water action and possible liquifaction of the coprolite margins.

 

The texture, combined with the flatness of the surface, makes me think that this facet is the only one that preserved the paleo-exterior of the coprolite. The remainder looks to have been water and sand worn during reworking. hard to tell from a photo, though :-)

[sharkdoctor]

PS You have the best poo-moji's 

[GeschWhat]

@sharkdoctor, I would so love to go poop hunting. Someday perhaps! I haven't been in a place with coprolites for a couple of years. I volunteer on digs with the Forest Service, but can't keep what I find because they are on public lands.  It is still fun.  I always bring my microscope so I can check things out back at camp and photograph the good stuff. Last year we were just in the lab and this year, of course, everything was cancelled. 

 

Poo-moji's...love it!  Can I use that? I try to give the coprolites on my website funny (or should I say punny) names. I have one that has the name "Prehistoric Poop Emoji" but "Poo-moji" would be so much better. I'll even give you credit if you would like.