Rhomaleosaurus?

The crude panorama above is taken from Sand Turn, on Highway 14 in the Big Horn Mountains of Wyoming, facing east on the left,  and south on the right.  You can see how the strata to the south has been uplifted by the mountains, almost as if they were waves lapping at the shore.  I've stopped at Sand Turn every time I've passed that way, to look out over the vast plains to the east.  One of my geology professors noticed the view, and remarked that he'd spent a summer geology camp there, and that one of the campers had picked up a large fossilized femur one day.  My brother's company was doing some surveying there, and mentioned that to the rancher.

In the summer of 1999, the rancher was using a cat to move rock from a limestone ledge, so that he could build a fence there, and he discovered this fossil (the coin is a USA Sacajawea dollar), approximately where the red v points in the middle of the panorama.  I carried it back to North Carolina, and showed to to a professor at the University of North Carolina, who referred me to a researcher at North Carolina State University, who referred me to Dr. David Martill of the University of Portsmouth in England.  I furnished photos, and a geological map of the area (prepared, partly, during the summer geology camps).  He suggested that it was a humerus with radius and ulna, possibly from an early Jurassic pliosauru such as Rhomaleosaurus, which would be the first such found in the United States.