This image is of some fossil teeth of the Sand Tiger shark aka Paleohyptodus rutoti (Winkler, 1874) on display at Mace Brown Museum of Natural History (August 2017). It dates to the Paleocene Epoch of the Paleogene Period. The fossils were maybe found in the rivers of South Carolina USA.
The
Mace Brown Museum of Natural History is located at the College of
Charleston, 202 Calhoun Street, 2nd Floor, Charleston, South Carolina
29424.
Learn more at their blog: http://blogs.cofc.edu/macebrownmuseum/