INTRODUCTION. xxiii 



boulder zone, as he calls the belt of masses of conglomerate, is what remains 

 of the elevated coral rock which has not been washed or dissolved away. 

 It is far more prominent at Minikoi than in the Maldives, but it does not 

 attain the importance it has in many of the Pacific atolls. Judging from what 

 I have observed in the Pacific, Mr. Gardiner is justified in assuming the ex- 

 istence of a lagoon in Minikoi at the time of its elevation, and in considering 

 the atoll to have been stationary for a considerable period of time on account 

 of the broad reef flat round most of its circumference. 1 



It is unfortunate that Mr. Gardiner should speak of a perfect atoll or of 

 a perfect reef. He thus characterizes not only Minikoi, but also Kiltan, 

 Chetlat, and Kavaratti among the Laccadives, and speaks of Cardamum as an 

 atoll either in a late or an early stage. Judging from the charts and in 

 analogy with the formation of Minikoi, he considers their present land con- 

 figuration due to elevation and subsequent erosion, as has been shown to 

 be the case for many Pacific atolls. We might indeed speak of Niau in the 

 Paumotus as a perfect atoll where the rim is continuous, or of Pinaki or 

 Maraki where we have only a small narrow boat passage opening through 

 the otherwise continuous wooded rim of the atoll. These atolls represent 

 a stage of growth which ultimately will end in the filling of the lagoon and 

 leaving a central shallow sink or pool as the only trace of the former 

 existence of a lagoon. 



While it is impracticable to subdivide atolls representing areas more or 

 less circumscribed by belts of land and of reefs awash, or submerged, they 

 vary from submerged banks through all the intermediate stages of banks 

 with crescent-shaped rims with or without islands to the so-called perfect 

 atolls with reef flats and passages and land rims. It seems to me mislead- 

 ing to refer to Addu as differing from all the other banks of the Maldives 

 and Laccadives in its more perfectly typical atoll form. Certainly Minikoi, 

 Goifurfehendu, Rasdu, Gaha Faro, Wataru, Makunudu are as typical atolls 

 .as Addu. 



Mr. Gardiner has given an account 2 of the mode of formation of atolls 

 which calls upon solution as the essential factor for deepening the lagoon of 



I Mr. Gardiner lias given a number of sections of Minikoi on page 30, loc. cit. , showing the width of 

 the reef flats at different points of the atoll. 



II Loc. cit., pp. 180, 181. 



