Folly Beach, Sc or Holden Beach, NC??

My husband & I are planning a road trip this summer and I would like to stop in one of the Carolinas for couple days. I love searching for sharks teeth and sea shells and I'm wondering which beach is better for that? Or if you know of another beach that's less known about but great for teeth & shells, that's great too! I'd like to visit both states but not sure we'll have time this trip. Thanks in advance!! <3