290 Nature and Bearings of Isostasy. 



stration that diastrophisin takes place by adjustment 

 between deep conical sectors, or that the continental 

 platforms originated in the manner advocated by Cham- 

 berlin. This statement, however, should not be taken 

 as a criticism of the planetesimal hypothesis. It is a 

 difference merely in regard to one important line of 

 deduction derived from that hypothesis. The data of 

 isostasy must ultimately constitute the test of that de- 

 duction. So far as now understood the isostatic data are 

 against it. 



It has been the purpose of these lectures to show the 

 methods of investigation which have given us a knowl- 

 edge of isostasy and of the relations which the theory 

 of isostasy bears to a variety of geologic problems, both 

 in regard to the structure and strength of the crust as 

 well as to the more ulterior problems of origin. 



