Concretions or Eggs

[WyoOtto]

Hi All,

I'm new to the forum and I have no paleontology experience other than a class from undergrad 20 something years ago.  My background is structural geology, hence my post here in hopes that I may confirm my suspicion as to the genesis of the specimens in the attached pictures.  First a little background: I was in the field yesterday doing some reconnaissance work in east-central Wyoming.  The land owners whose property I was on are multi-generational ranchers and they were extremely welcoming and enthusiastic about the geology of the area, despite having limited knowledge.  At the end of the day, standing in their yard saying thank you's and goodbye's one of the college-age sons came running up with 2 specimens of what I presume to be concretions.  However, the texture was smoother than other concretions I have seen and there was a dimpled character to the extremity of both which I found odd.  The kicker is that the southern end of their property has a full section of Jurassic Morrison Fm exposed.  When I asked what the rock looked like in the area that he found them, his description matched what could be interpreted as the variegated sands and shales of the Morrison Fm.  Of course, it could also describer some of the Miocene sediments unconformably overlying the Cloverly Fm in the area as well. 

 

Regarding the photographs attached:  I did not take the specimens with me, only the photos attached with my phone in the land owner's front yard.  Therefore I do not have scale other than to say the index finger of my left hand is 9.5 cm and my left thumb is 7 cm from tip to base knuckle.  Any help would be greatly appreciated as I told the landowner's son I'd be happy to do a little research on his behalf.

 

Much thanks in advance!

 

-WyoOtto

[WyoOtto]

[jpc]

Hi WyoOtto, and welcome from Casper.  

We get a lot of "Is this an egg?" Questions here.  Most of them are not.  This one is a tougher one.  It looks awfully eggy, but just not the right texture.  The texture between your extended index finger and thumb is tempting, but I see nothing eggy in any of the other photos.   

 

My opinion is biased, as there are no eggs known from the Morrison of Wyoming,and none or not many known from other states.  I think there have been eggshell pieces reported, so I come at this form ... "If this is a Morrison Egg, it would be a spectacular find".   

 

If you want, feel free to tell the rancher and/or his kid to bring it by the Tate Geological Museum in Casper.  We would be happy to have an in-person look at this thing.   

[Troodon]

I'm also not seeing any eggshell matetial along the crack in your second photo.  It would be a few millimeters thick.  Cool item and I would also encourage them to take it to the Tate Museum.

[WyoOtto]

Thanks for the quick response guys!  I will absolutely encourage him to take them to Tate for further investigation. He said he found them within a foot or 2 of each other and couldn't find any others which was another compelling bit given that usually in a horizon with concretions, it takes little effort to find quite a few (or at least that's been my experience).  Regardless, Tate is an excellent suggestion and I will pass it along.  Thanks again!

[jpc]

and when they get here, feel free to have them tell us it was posted on The Fossil Forum.  At least one of us will know what that means (assuming I am here at the time). 

 

[WyoOtto]

Hi JP,

I spoke with the landowner and recommended they go visit you at the museum the next time they are in Casper. I got the impression that the son was excited enough about it that he might make a special trip to come see you.  I also mentioned the forum.  

 

Thanks again!

-Aaron

[jpc]

17 minutes ago, WyoOtto said:

Hi JP,

I spoke with the landowner and recommended they go visit you at the museum the next time they are in Casper. I got the impression that the son was excited enough about it that he might make a special trip to come see you.  I also mentioned the forum.  

 

Thanks again!

-Aaron

Feel free to have him give me a call to make sure I am here.   I am PM-ing you the phone number