president's address — SECTION c. 91 



feel that I need crave no special indulgence in asking you to con- 

 sider shortly what is the true structural boundary of this pro- 

 found ocean basin. 



Our knowledge of this the greatest of the earth's features is 

 still slight indeed. Its vastness must stimulate the imagination 

 of all. No one can help wondering whether it has always been 

 so immense. We cannot fail to question whether our distant 

 lands have not in the past joined hands and pressed forward into 

 the confines of this watery waste. 



It is well known that the Pacific Ocean is, generally speaking, 

 of great and uniform depth. Its floor is almost everywhere 

 between 2,000 and 3,000 fathoms below the surface of the water, 

 and the few scattered islands that rise above the troubled waves 

 are either mere volcanic peaks or structures due to the activity 

 of coral-making organisms. 



Many speculations have been indulged in to account for this 

 most mighty of all physical features of the earth's surface. They 

 have been based in some cases upon cosmical speculations, for 

 Professor Pickering has lately suggested that the ocean basin is 

 the scar left by the moon, which Darwin has shown was derived 

 from the earth. ^ Jeans and Sollas have regarded this basin as 

 actually inherent in the pear-shaped form that the earth assumed 

 in cooling. On the other hand, Suess regards the immense depres- 

 sion as a subsidence area which has been in existence since the 

 Triassic Period. He thinks that it marks a region where the crust 

 of the earth has fallen in owing to lack of support afforded by a 

 shrinking nucleus. 



Other authorities have taken less extreme views of its 

 antiquity, and these are typified by Captain Hutton, who would 

 construct a land bridge across the ocean between New Zealand 

 and South America at no distant period in the past in order to 

 explain the resemblances between the flora and fauna of tropical 

 South America and those of New Zealand. 



Great as are the differences of opinion in regard to the age and 

 the permanence of this great basin, those in regard to its structure 

 are at least equally great. They are mainly founded upon the 

 positions of the groups of minute islands with which the surface 

 of the ocean is dusted. It is well known that the islands of several 

 groups have a definite linear arrangement, and this has naturally 

 suggested that they are nothing more than the emerged summits 

 of mountain ranges. The linear arrangement of different groups 

 is usually more or less parallel, and the further generahsation has 

 somewhat naturally followed that they constitute parallel ranges 

 of a mountain chain in which the dominant trend is W.N.W. to 

 E.S.E. 



In making such statements little account has been taken of 

 the soundings in the surrounding ocean. It is also noteworthy 

 that too much importance should not be attached to the arrange- 



1 Pickering : Journ. Geol., XV., 1907, p. 23; Sollas: "Age of the Earth." p. ; 

 Suess : "The Face of the Earth," II., p. 553. 



