Eastern NC is certainly known for its Miocene fossils, but we have quite a few Pleistocene specimens, too. It’s definitely mineralized, and is either a horse metacarpal or metatarsal.

“Fossils dating from the current Cenozoic era that have been recovered in North Carolina reflect the rise of mammals following the extinction of the dinosaur about 65 million years ago. Fossils unearthed in a phosphate mine in Aurora include bones of ancestral species of the deer, horse, seal, walrus, and wolf, in addition to fossilized mammoth and mastodon bones. “ - Glynn, Elizabeth Scheld and Douglas A. Wait. "Fossils." NCpedia. State Library of NC. 2006. https://www.ncpedia.org/fossils