Very Rare Find Fossil Shells

[Isidro]

I saw pieces of drifted rare oyster shells in the seashore of an island on the southern part of Leyte (Philippines).
Another complete pair of oyster shell which embedded the rocks offshore has been found and within it has a black and pearl. I believed through its appearances that all are pre-historic oyster pearls which I consider a treasure in the island.
Need your help to identify each if these are anything of value.

 

[GemGeek]

Shells are interesting, but not especially valuable.