Bay salt, a term now little used, meant sea salt (which in practice does usually come from a bay) produced by natural means, i.e. salt produced by the heat of the sun playing on sea-water in shallow basins or reservoirs. See Webster (1861). The bay originally intended by the term was Bourgneuf Bay, south of the mouth of the Loire River, where salt production dates back to the 14th century.
Black salt (kala namak) is a salt used in India which is brownish-black in lump form but pinkish-brown when powdered. It is liked for its special taste and what has been called a ‘smoky aroma’ but more accurately might be described as sulphurous.