Oklahoma Mammal Bone Id Please

[Tulsa Clovis]

Hello, I am an artifact hunter from Oklahoma. I found this bone while hunting for artifacts at a gravel mining operation where they are digging deeply into a sandy river bed. I have found numerous mammoth and mastodon tooth fragments as a result of their mining operation. I frequently find ancient bison bones and can tell the difference between a heavily patinated un-fossilized ancient bone and a mineralized bone. The bone fragment in question is very mineralized and is as heavy as stone, it also has sand/gravel that has become cemented to it in a couple spots, this is something I never see on non-pleistocene bison bones from this river, but similar cementation is common to see on mammoth and mastodon teeth from the same river. Can anyone tell what animal this bone fragment is from? Thanks in advance!

[Xiphactinus]

That's definitely from a big critter and looks like it has some age. Not sure at all on this ID, but could it be the head of a mammoth/mastodon rib?

[RichW9090]

There's something whispering "pelvis" to me, but I can't precisely place it without having it in hand.

[wfrr]

Based on the pics I feel certain it is a mammal

[Tulsa Clovis]

I have found lots of fossilized bone fragments with no identifiable characteristics, but i was hoping this one had enough diagnostic features that someone might recognize it.