COPROLITE

Awesome display sir!

LOL, I think I'll endeavor to post a specimen every Tuesday. Before we're done we'll all be petrified poo connoisseurs.

I should point out that all the specimens I deal with, to the best of my knowledge came from herbivores. There is no reason for this except it's just what's available to me where I search. As far as I know I could have been walking right by carnivore turds and just not recognized them for what they are.

When I'm searching for coprolites my eyes seem to disregard other rocks that I probably ought to be looking at.

I found a lovely website on coprolites:
Coprolite Poozeum

Lots of info and photos.

I thought raisin nut bread!!

I only know what I've learned here about dino poo, so please bear with me. I'm interested to know what sets this one apart from a conglomerate? Thanks!

That looks like some of the conglomerate I collected West of the airport by Moab, Utah.

Natural Concrete
That conglomerate was from a layer of sediment laid down millions of years ago

Good and valid question Eric. I wrestled with that question when it came off the saw. Fortunately I had access to a deep knowledge base from several old timers who have years of experience in the subject.

Not only do we look for clues within the specimen, we look for clues within the formation where it came from. In this scenario we not only learn from what is present within the specimen and it's host formation, but we also learn a lot from what is NOT in the specimen and it's host rock. I like to call this the "context" of where a specimen is found.

The layer I gather from is a fairly homogeneous strata of sandstone with alternating layers of petrified banks of quartzite beach gravels mixed with sand. The different layers in this locale are consistent in the components with very little variation that make up their whole. Because of this consistency it's fairly easy to spot anything out of place. I rely upon this heavily.

There are no agates in these layers except for coprolites and agatized wood. In this area if you want to identify if a rock is coprolite you knock a chip off with the hammer and look inside for agate because almost all other candidates will be sandstone inside.

Do this enough times and you begin to see there is a definite phenotype to coprolites and to continue hitting them with a hammer is unnecessary. Within a short time almost any novice can readily identify a coprolite in this locale just by the appearance of its exterior.

Now concerning the specimen in question ... I relied much on its exterior shape. There is virtually nothing within its host strata, or superior strata that has this distinctive shape except for other coprolites. This was my first and most compelling clue. In years of searching through miles of this strata I had never before seen anything resembling it except for other coprolites, thousands of them.

My second clue was when I polished the cut faces on a flat lap it produced undercutting around the perimeter of each gastrolith which was consistent with other specimens containing gastroliths. The gastroliths are almost always made of the tough cobbles of quartzite that seem universally tougher than the agate surrounding them.

The next clue was when I put the cut surface under the microscope it became apparent that each of the many gastroliths was surrounded by agate instead of sand. This clinched it for me because I know that in this place the sole source of agate is where plant or animal tissue absorbed silica probably from the surrounding sand or later ash falls superior to that level. I should add that I occasionally find dino bone associated with coprolites and it's agatized to a very similar nature.

Finally, I showed the specimen to my old timer friend Denzil Hammer, who has published numerous articles on coprolites and has sold many tons worldwide ... he looked at it and said "yep, it's crap." I suppose it might be.

Thanks. That cleared up my question and any other questions I may have had! Excellent information