Found this piece while walking on a newly excavated (6-8 inches deep) plains path about 30 miles southeast of Boulder, Colorado. I'm new to the area and trying to ramp-up on the geology and fossils with limited background knowledge but much time being retired. Overwhelming and fascinating! Several hikes to Dinosaur Ridge and Dr. Bakker's museum in Morrison. To my untrained eye it looks like a rib or similar flat bone piece. The dark interior color and texture seem somewhat "different" (?).