The famous Blue Grotto on Capri contains 

 clues to the remarkable cycle of sub- 

 sidence and uplift that has occurred 

 around the Bay of Naples. When the Romans 

 of the first century B.C. used the cave, 

 its floor was at least twenty feet 

 higher than it is today. The mysterious 

 blue light that fills the cave is thought 

 to come through the submerged 

 Roman entrance. 



level, but it can be penetrated only by very small boats, and the 

 mysterious blue light of the cave is best seen when this entrance is 

 closed. The Blue Grotto contains within it all the clues to the 

 remarkable cycle of subsidence and uplift which has apparently 

 occurred all around the Bay of Naples. How far this cycle can be 

 traced to the north and to the south of Naples has yet to be 

 determined by someone. 



Philippe Diole, the learned French journalist, was only too well 

 aware that it was useless to attempt anything in underwater archae- 

 ology without adequate finance and modern machinery. His book, 

 ^0 Years Under the Sea, is the most thorough survey of the topic 

 to date, and in it he shows how rare it is to have interested archae- 

 ologists, adequate finance, suitable equipment, trained divers, and 

 enough time, all focused on the same site. While this may sound 

 simple to achieve, it seldom happens in practice. 



Diole is such an individuaUst that, rather than dive with a team, 

 however reliable, he prefers to work alone to savor in oceanic 

 solitude the presence of the past. His most important work has 

 been on the ports of Saint Tropez, Marseilles, Fos-sur-Mer, and 

 Cherchel. 



At Saint Tropez (ancient Athenopolis) there is an ancient stone- 

 mason's yard about 650 feet from the shore and in a depth of about 

 twenty feet of water. What caused this change of level and when it 

 occurred are unknown. In September 1950 the Club Alpin Sous- 



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