6.8" Fossil Running Rhino (Hyracodon) Upper Jaws - South Dakota

This is a beautiful, 6.8" long partial upper skull of Hyracodon sp. ("running rhino"). It was collected from the Brule Formation in Pennington County, South Dakota, and would be approximately 30-34 million years old. The specimen features a partial upper skull still incased in rock with the teeth exposed.

One edge of the rock has been cut flat and covered with a plaster, allowing it to sit nicely on a flat surface while displaying the teeth. Most of the molars have undergone some breakage.