CONTINUITY RELATIONS 



853' 



geosyiicliiies as for isostasy — that is, some greater force caused them and 

 ended them. 



The same general relations militate with almost equal force against 

 the theory that geosynclines eansed momitain folding, for it is clear that 

 the establishment of a geosyncline in one region was no bar to the shift- 

 ing of it in later times into different and even distant regions. Nor was 

 it a bar to transformation of a geosyncline of deposition into a landmass. 

 There were, therefore, other forces at work which produced geosynclines, 

 shifted them, and even reversed them. These forces were the ones that, 

 finally caused the great folding ; their early manifestations were the geo- 

 synclines and their associated geanticlines. .The geosynclines played^ 

 their part in mountain-building, however, for their thick deposits gave 

 opportunity for and character to the folding. The depressions of the 

 rigid crust in the geosynclines helped to determine the position of fold- 

 ing, but they were themselves the expression of an already active force. 



CONTINUITY RELATIONS 



The relations of the various hypotheses to the element of time is most 

 important. The facts of geology determine the relative position in the 

 time scale of the great movements of the crust. These are not continuous 

 but are periodic and separated by unequal intervals ; they are not of equal 

 force but they differ as 100 to 1. Presumably, therefore, their causes 

 differ in nature or amount. The forces apjoealed to for cliastrophism are 

 continuous, however, the sole exception being the partition of the moon, 

 from the earth, as suggested by some writers. The possibility of parti- 

 tion, as worked out by mathematicians, puts it far back of the Paleozoic, 

 so that it is not a competent cause in post-Paleozoic deformation. Nor 

 could a capture of the moon by the earth, as has also been suggested,. 

 account for more than one of the great diastrophisms. It has not yet 

 been suggested that the partition of the moon caused Paleozoic diastro- 

 phism and its capture again caused that of the Tertiary. 



While the various oscillations during the Paleozoic may be appealed te- 

 as evidence of the storing up of forces to be later released, these pre- 

 liminary movements are wholly out of scale with the final movement. 

 What we should expect from a storing up of such forces as contraction, 

 which is of steady growth, would be rhythmic action with its culmina- 

 tions of roughly the same intensity. This is for the reason that the ma- 

 terials of the crust have not changed their character materially since the 

 beginning of Paleozoic time. Their capacity for storing up strain, there- 

 fore, had a definite maximum, and release should have occurred whenever- 

 that maximum was reached. It shoukl not have been distributed througk 



