THE ATOLL AS A WHOLE 137 



The group consists of two separate atolls : — a small 

 atoll to the north, which is Keeling Island proper ; and a 

 larger atoll, some 15 miles to the south — the Cocos atoll. 

 The information concerning the changes in the atoll to be 

 derived from old charts is practically nil, and it is a great 

 mistake to place any reliance on what are, after all, only rough 

 sketch-maps made by passing mariners. In some cases de- 

 ductions have been made as to changes that are presumed to 

 have taken place in the atoll, by noting the differences which 

 exist between these old mariners' sketch-maps and modern 

 charts. Such deductions are liable to cause grave error. In 

 some cases such errors have been caused, and mention will be 

 made of these as the subject comes under discussion. 



The group lies in the eastern portion of the Indian Ocean, 

 12° 9' south of the Equator, and 96° 53' east of Greenwich ; it 

 is separated by some 600 miles from Java; some 500 from 

 Christmas Island ; some 2000 from Cape Leeuwin, Australia ; 

 and by about the same distance from Ceylon. 



The atoll lies in the track of the South-East Trade winds, 

 which blow for 300 days in every year ; and in the Westerly 

 Equatorial sea drift, which flows constantly past the islands. 



Various accounts of the atoll have appeared from time to 

 time, and its name must always remain associated with the 

 theories of Charles Darwin, for when he made his visit in the 

 year 1836 he saw, in certain features of the atoll, all the signs 

 that he had previously pictured as being the evidences of 

 gradual subsidence. It was the only atoll that Darwin ever 

 examined, and it was the one on the examination of which the 

 famous theory of " Subsidence " was founded. 



Dr. H. 0. Forbes visited the islands in 1879, and the out- 

 come of this visit was the interesting account which appeared 

 in " A Naturalist's Wanderings in the Eastern Archipelago," 

 published in 1885. 



Dr. H. B. Guppy made a stay in the group in 1888, and 

 has published by far the best account of the actual structure 

 of the atoll in the Scottish Geographical Magazine, vol. v., 

 Nos. 6, 9, and 11. 



