Limpet shells

Limpet shells, originally uploaded by andiwolfe.

All along the coastlines of South Africa, where dune fields also occur, one finds limpet shells piled up in the first swale of the dunes. This is usually several hundred feet away from the beach, and up dozens of feet from sea level.

I wonder if these are deposited by gulls or other creatures who eat the animal and leave an intact shell. It's a mystery to me.