80 Scientific Intelligence. 



(Wharton Deep). The island is described as forming the summit 

 of a submarine peak, the base of which rises from a low saddle 

 which separates the two abysses named, and on the western end 

 of which the Cocos-Keeling Islands are situated. Its peculiarly 

 isolated position, hence, is most striking. Its history is also 

 unique, since, although known to navigators since the middle of 

 the 17th century, no one seems to have penetrated into the inte- 

 rior until 1887, and, as remarked by Dr. Murray, down to a few 

 years ago it was probably the only existing tropical island of any 

 large extent that had never been inhabited by man, savage or 

 civilized. Its animal and vegetable life, therefore, are thus far 

 almost unchanged by the conditions introduced by human life. 



Geologically, the island consists largely of elevated Tertiary 

 limestones with extensive series of eruptives ; briefly, it may be 

 considered as an ancient atoll raised to a considerable height 

 above the level of the sea. The " central nucleus " is made up of 

 compact yellow limestone in places very hard and showing no 

 traces of bedding or jointing. This is referred to the Eocene (or 

 Oligocene) and is accompanied by basalts and trachytes both 

 beneath and between the beds. The total thickness of these 

 older Tertiary and accompanying volcanic rocks is estimated to 

 be 600 feet. Forming the mass of the island is the Miocene 

 Orbitoidal limestone, separated from the older rocks by basalts 

 and basic tuffs. The higher elevations are dolomitic limestones 

 containing 34 to 41 p. c. of magnesium carbonate; these show 

 traces of coral structure and imperfect remains of Foraminifera. 

 Thick beds of phosphate of lime, in part limestone beds altered 

 by overlying guano, in part phosphatized volcanic tuffs, occur on 

 some of the elevated points and have proved to be of economic 

 value. The Tertiary limestone, especially the Miocene, forms 

 abrupt vertical cliffs, sometimes 250 feet in height, along a large 

 part of the coast line. A series of terraces is also noted around 

 the shore, and outlying the whole is the fringing coral reef. 

 The author remarks upon the remarkable development of ele- 

 vated Tertiary rocks and the difficulty in explaining their deposit 

 over an area so isolated. He adds that the great thickness of 

 reef limestone, required by the Darwinian theory of atoll forma- 

 tion, is not found, and although there may be some evidence that 

 subsidence did occur in the history of the island, it is clear that 

 it was not for any long period nor of any great extent. It is 

 interesting to recall in this connection the similar observations 

 recently made by Agassiz on the elevated Tertiary limestones of 

 the Fijis and other islands of the Pacific. 



The life of the island is fully described from the collections 

 made and it is shown to be to a remarkable extent endemic. 

 Thus of the 319 species of animals recorded, about 45 percent are 

 described as peculiar to it, although this [percentage may per- 

 haps be reduced when the fauna of Java and other neighboring 

 islands is more minutely known. For example, of the mammals, 

 all are peculiar species except one ; of six reptiles, four are pecu- 



