"Dino Egg" Rock from southern Utah

[TSinCO]

Southern Utah - Grand Staircase between the Vermillion and Chocolate cliffs section.  The geological period for this location is Upper Triassic.    I was out exploring the cliff of a butte (more like a half-butte since one side was cliff and the other gently slopes north into alluvial sand) and came across what seemed like a very flat ancient creek bed, now just a small desert wash.  It was strewn with quite large river rocks that did not belong, and were not found outside this sand creek.   It was very cool, as this "river" was essentially at the top of the cliff and gently flowing away from the edge, so even heavy desert monsoons couldn't produce enough run off water flow to smooth these rocks since the cliff formed.   Whatever mountain these rocks came from is long gone.    

 

I came across this egg-shaped rock.   (8-12inches, 20-30cm long) , and the surface markings were really unusual.  I took the photo below, but was being dragged along by my partner who couldn't care less about rocks, so I didn't get forensic photos.   I assumed in the moment it was just a very egg-looking river rock, even though it was a different type than the others.  The cliff area was otherwise entirely the typical sedimentary rock you'd expect.   But after a year looking at the photo, and looking at actual dino eggs, it didn't seem like a totally crazy thought.    Petrified wood is known to be in the area also, but I wasn't aware of that at the time.

 

I attached a photo of the other rocks in the sand creek to set the scene a bit.  Some of these rocks looked like they really needed to be broken in half to see what might be inside, but I didn't have my rock hammer as I thought I was just going to see normal sandstone.

 

Thanks for any thoughts...

 

 

[Troodon]

Beautiful area.  Not an egg looks like a very cool waterworn rock.  Others who are familiar with them may comment on its makeup.  Eggs would contain a thin shell material and are super rare especially from the Triassic

[abyssunder]

Just seen the topic, there are very nice percussion marks on the surface! 

[Mark Kmiecik]

You can tell it's not an egg because with a shell that thick, the embryo would need a jackhammer to break it's way out. Also, an eggshell has pores all over it's surface through which the embryo "breathes". There is no evidence of that here. And finally, an eggshell would never, ever, under any circumstance crack in near spherical or fish-scale-shaped pieces under any kind of pressure or force created by nature or even manmade. Go ahead and try it! Not possible.

Edited July 7, 2022 by Mark Kmiecik