Old Poo?

[JoshinMO]

Plant Eater pellet or rock? :dunno:

[CMD]

My guess is rock, not fossil.

[Erik Hayden]

Looks like it could be, examine it to see it there are any fibers of vegetation. Plant fiber should be visible.
I've got a dinosaur coprolite, it shows the blood, fat and whatever else was in it's stomach when it died.
My uncle is a geologist and verified this as real dinosaur poo.

[painshill]

I’m pretty sure the original item posted is just a rock. It looks like selenite, gypsum or barite concreted with sandstone. Something like this (this one is selenite):


[pic from Gresham’s Gypsum Rosette Page hosted on the Earlham College website]

It doesn’t have any of the characteristics of a plant-eater coprolite that I can see.


Frankly, I’m also doubtful about the second item being a coprolite. Where’s it from? Morrison Formation? The vast majority of so-called dinosaur coprolites are misidentified agate pseudomorphs of carbonate soil nodules. They may have what looks like plant remains in them. I don’t see anything in that one which is diagnostic of either herbivore or carnivore coprolite. For a carnivore, you would need to see fossil bone fragments, fur impressions, fish scales or something more definitive. What you see in that specimen for sure isn’t fossilized blood, fat or whatever. That simply wouldn’t be recognisable in fossil gut contents and certainly doesn’t come out the other end undigested in a coprolite.

[Pele]

I agree with Painshill on both accounts, and I am also a geologist. The second one definitely looks like chert to me.