This image is of some fossil plyllodontid fish dental plates aka Phyllodus toliapicus (Agassiz, 1839) on display at Mace Brown Museum of Natural History (August 2017).
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/