I46 NEW YORK STATE MUSEUM 



which is by far the longer in the Eurasian system, exhibits an equally 

 distinct northwest direction, or just the diametrally opposite 

 direction from that postulated; and the central section of Laurentia 

 possesses an east-west direction that is entirely indifferent to tidal 

 influence. 



Possibly one might consider the north-northeast direction of the 

 folds in India, and a like direction in the Colorado and Bohemian 

 massives, as indications of a tendency of the north-south equatorial 

 direction to change to northeast. It would, however, require the 

 evidence of an entire circumpolar belt of this direction to prove 

 the case. 



It is further to be remembered that the assumption of body 

 tides powerful enough to fold the crust would postulate a con- 

 siderably greater nearness of the moon and a less rigid condition 

 of the earth crust in Precambrian time than there is reason to assume 

 on other grounds. Finally Chamberlin (1909, p. 25) has pointed 

 out that there is a large body of geological evidence which seems 

 to indicate that the lithosphere is able to accumulate stresses for 

 long periods, which are then relieved by permanent deformations; 

 continuing, "it is difficult to understand how an earth could be 

 possessed of this ability if it yielded fluidally to such transient and 

 moderate stresses as those of the tides of the outer part of the litho- 

 sphere. We therefore assume with confidence that, whatever the 

 amount of the lithospheric tide, it is only an elastic strain which 

 relieves itself almost instantly on the removal of the force which 

 caused it and involves little friction." 



As neither the retardation due to the tides nor the acceleration 

 of the rotation due to shrinkage of the earth were found to be com- 

 petent to account either for the direction or for the amount of the 

 Precambrian folding of the equatorial and circumpolar belts, it 

 follows, by exclusion, that the shrinkage appears to have been the 

 sole cause of the folding, and the existence and configuration of the 

 continental and oceanic segments the controlling agency in the direc- 

 tion of the trend lines of the folds. 



Bibliography 

 Abendanon, E. C. Aequinoctia, an old Paleozoic continent. Jour. Geol. 1919, 



27:562 

 Adams, F. D. The basis of the Pre-Cambrian correlation. Jour. Geol. 1907, 



17:115 

 & Barlow, A. E. Excursions in the Eastern Townships of Quebec and the 



Eastern Part of Ontario. Guide book no. 2. 19 13 



