identify types of conch shells, some very old

[Shells85]

Thank you for helping me identify the different types of shells (conch I think). The first row look very very old and almost like clay. Also, if possible could you tell me if any are uncommon.
Thank you

[Shells85]

is it possible top row of old shells are :Caloosahatchee Formation Florida Authentic Gastropod Fossil Stromus floridams

[paul monfils]

The first row, from their appearance and your description, appear to be fossils. Perhaps Strombus floridanus, though I don't know much about fossils.
The second row appears to be two Strombus pugilis and one Strombus lentiginosus. The latter shell is the only one in the photograph that is not from Florida/Caribbean.
The third row, badly worn but probably Strombus raninus.
Fourth row, very worn, could be S. pugilis, or perhaps a fossil predecessor of S. pugilis.