Looks like a bullet hole in that one.
The entire bone including the hole and the broken end is evenly worn down to a Polish..water find?
The other is a segment of interior turtle shell...that's part of its rib structure on the concave side.
Thanks for the feedback and input!
I see what your seeing but I think it's deceiving .. every surface of that bone piece including the edges that would have showed the lattice work of bone structure are evenly and completely worn.
Including what would have been a chip that gives the appearance of a drill starting at an angle and the edges of the hole.
Given the amount of wear on the entire surface any evidence of being drilled by stone would have been completely worn away.
That's just my take on it.
The second piece is most definitely a section of turtle shell.. the beaches and shorelines here are strewn with them.. no work has been done to it.