Hell Creek (Powder River) - Mystery Skull (?) piece?

[rkfrace]

Good day.  Recently got this mystery specimen from the owners of an extremely productive and well-known ranch in Powder River Country, Montana (please see photos).  The specimen was found by the owner.  

 

Unfortunately, this specimen is not like those.  Here's the only additional info:  

 

"This large piece of skull [?] was found in one piece. Weighs approximately 4 lb. 3 oz. The measurements are L 7  2/10" W 4  3/4" No repairs. Color is various shades of brown. Some of the openings actually have some matrix in them, but I left that, in order to stabilize the thin walls." 

 

I know it's particularly hard to ID a piece like this from photos, but if you have any ideas, I'd deeply appreciate them!

[Troodon]

Difficult to say what you have especially with the matrix still around the bone.  I would suggest you remove as much matrix as possible and send the images to Pete Larsen.  He might have a better perspective on this skull element(s).