606 T. C. CHAMBERLIN 



massing and careful adjudication of data from all parts of the 

 world, for the sanction of the method will largely depend on 

 its success in conforming to and elucidating world-wide phe- 

 nomena. Both this and the preceding method will require 

 first to be established by trial before they can be independently 

 applied, but this was equally true of the paleontologic criteria 

 at the outset. 



The very establishment of these atmospheric and oceanic 

 criteria, or their disproof, would go far to settle the fundamental 

 question whether the earth's history is naturally divisible into 

 periods or not. If there be secular accumulations of stress in 

 the body of the earth, followed by adjustments when rigidity is 

 overcome, and if these adjustments change the respective areas 

 of land and sea, and these in turn result in changes in the con- 

 stitution of the atmosphere and in the evolution of life, these 

 cycles must be factors in the ultimate basis of a rational classifi- 

 cation of geologic time, and must at the same time express some 

 of the most profound and significant features of the earth's 

 history. 



The doubt as to whether these things be so or not can only be 

 resolved by studies as broad as the earth. Such studies are 

 not only international and intercontinental, but they are omni- 

 terrestrial. The shaping they have been given here is that of an 

 individual student and expresses his limitations, but the breadth 

 and importance of the problems themselves will not be ques- 

 tioned. 



Now it is far beyond the functions and the resources of any 

 present official organization to adequately cope with these great 

 problems. There is not even an organization at present that is 

 provided with the men and the means to bring promptly together, 

 arrange, and tabulate for the common benefit of geologists the 

 data that are being gathered by official and private investiga- 

 tions ; much less is there any organization that can build these 

 into their organic relations, or draw forth from them their full 

 significance and make this serviceable in further investigation. 

 Nor is there any organization provided with any notable means 



