Subterranean Sea?

It has long been known that there was abundant water underlying the Sahara Desert, for artesian wells sunk at many points in the great waste, both by the French authorities and by natives, have invariably proved productive. Now, marine life has been found in water drawn from some of these wells--small crabs, fish and shellfish. They are not blind or otherwise abnormally evolved to meet subterranean conditions, as are some of the animals found in Mammoth Cave. But they belong to normal surface species known to inhabit the lakes of Palestine. The excavators are puzzled, but advance the theory that the whole of North Africa is underlain by a subterranean sea, 300 feet beneath the surface, connected by passageways with bodies of water beyond Suez.