Boys' adventure sf novel.

''working name of UK writer John Clifford Bayliss (1919-1978), the young protagonists of whose ATLANTIS ADVENTURE (1958) discover the eponymous Lost World in an oceanic trench in the Caribbean Sea, where they discover ancient relics, sea monsters and robots; unfortunately, their experimental nuclear submarine breaches the walls keeping the ocean at bay, though the youths make their escape''(John Clute/Encyclopedia of SF, 3rd Edition).