590 



WILLIAM J. MILLER 



Falls contorted zones in 1908, and further elaborated in 191 5."^ 

 Arguments against Hahn's h3^othesis are there entered into some- 

 what in detail. In the opinion of the writer, differential movement 

 (not always as an accompaniment of thrust faulting) is involved in 

 many, if not most, cases, of intraformational corrugations. 



Intraformational contorted beds of essentially the same origin 

 as those at Trenton Falls, only on a larger scale, occur within the 

 straight-bedded limestones of Turtle Mountain, Frank, Alberta, 



Paleozoic timestop^ 



Cretaceous jhates and sgpdsiopes 



Fig. 2. — Section showing the position of the contorted limestones and the relation 

 of the contorted beds to the great thrust fault at Frank, Alberta, Canada. (After 

 R. W. Brock.) 



Canada. Accompanying Figure 2 after Brock^ shows the position 

 of two corrugated zones of more shaly material intercalated between 

 straight beds of limestone and parallel to a great thrust fault on its 

 upthrow side. The writer would explain these corrugations as 

 due to differential slippings within the limestone with resultant 

 crumpling of the more shaly layers during the process of thrust 

 faulting of the Paleozoic limestone over the Cretaceous strata. 



Many years ago Logan,^ in his description of a section 1,210 

 feet in thickness of Devonian strata on the Forillon peninsula of 



' W. J, Miller, N.Y. State Miis. Bull. 177 (1915), pp. 135-43. 

 ^ R. W. Brock, Dept. Interior Canada, Ann. Rept., Part 8. 

 3W. Logan, Geol. Can. (1863), p. 391. 



