I added up the gastropods that do not have a good identification in Harry
Lee's list of marine shells of northeast Florida (www.jaxshells.org).
They comprise 79 of 539 species, or over 17%!  With all the time and
attention given this list, I assume that the shells not identified will
not be identified short of major monographs to straighten out the poorly
understood names, still leaving many new names needed. And this is an
area which has been explored and written about extensively.  You don't
need to go to exotic locals to find new species!