Here is some info and perspective from Dave Bohaska @dbohaska of the Smithsonian
Hi Bruce:
Will find all the Belgrade material here; I think we can count them on the fingers of one hand. My notes of 22-23 May 2015 mention the astragalus that Victor found, and an enamel fragment also. The next day Kyle Grimsley in brought a partial horse upper to the Festival, which my notes say you saw. Good idea putting the notice out on myFossil. Be prepared to see Pleistocene mammals.
Couple odontocete periotics were found on that trip also, so we can conclude there are at least two species. More identifiable marine mammal material has turned up on the NC coast in Upper Oligocene limestone, which is close or the same formation lower in the quarry. Oligocene or Lower Miocene, key time in the evolution of cetaceans.
The stratigraphy there has me confused. Formation names are going back and forth, and that layer is put in the Upper Oligocene by Buck Ward.
-Dave