140 NEW YORK STATE MUSEUM 



7 No clear drag or gliding zone is visible, but rather there is 

 often gradual transition between the contorted zones and the over- 

 lying strata. 



DISCUSSION OF THE HYPOTHESES 



Certain points not mentioned above as well as others requiring 

 fuller discussion will now be considered. It is not the purpose of 

 this paper to deny that, under proper conditions, subaqueous slump- 

 ing, with resulting contortions, may take place, but it is our concern 

 to show that the contorted zones at Trenton Falls do not admit 

 of such explanation. 



An important fact, which in itself is well-nigh fatal to the hypo- 

 thesis of submarine slumping, is that the slope of the sea bottom 

 on which deposition of the Trenton beds took place was altogether 

 too slight. The writer has presented detailed evidence to prove 

 that, in the Trenton Falls district, the sea bottom receiving Trenton 

 deposits was remarkably smooth and with greatest slope toward the 

 southwest at the rate of only 6 to 20 feet a mile. 1 Similar evidence 

 for the adjoining Little Falls 2 and Port Leyden 3 districts by 

 Cushing and the writer show respective slopes of only 6 to 10 and 

 about 30 feet a mile. Considering a slope of 12 or 15 feet a mile 

 at Trenton Falls, this is 30 to 40 times less than the slope (4 to 6 

 degrees) in Lake Zurich, which Hahn cites as a remarkable instance 

 of very slight slope upon which slumping occurred. In fact the 

 floor of the Trenton sea in the vicinity of Trenton Falls was so 

 nearly perfectly horizontal that any such slumping or gliding of 

 masses, as required by Hahn's hypothesis, could not have taken 

 place. 



But, even if we grant the possibility of submarine gliding, an- 

 other difficulty stands in the way, namely, that the gliding masses, 

 as judged by the obvious criterion of strikes of small folds within 

 the contorted zones, must have slumped off toward the northwest 

 when, as a matter of fact, the greatest slope of the sea bottom was 

 at right angles to this, or to the southwest. 



Emphasis is placed by Hahn upon the fact that the materials of 

 the contorted zones are not notaibly different (weaker) than the 

 inclosing materials. While differential motions would certainly 

 tend to concentrate along distinctly weaker belts, such belts are not 

 deemed absolutely essential because the slipping once having even 



1 N. Y. Stale Mns. Bul. i_'(). p. 36. 



2 N. Y. Slate Mns. Bul, 77, p. 01. 

 :t N. Y. State Mns. Bill. [35, p. 43. 



