252 H. L. FAIRCHILD PLEISTOCENE UPLIFT OF NEW YORK 



No way has been found of explaining these figures except by a local 

 wave uplift in the Watertown-Trent River region while under Iroquois 

 waters which were comparatively stationary. If uplift had been in prog- 

 ress while ice lay over the Covey district and Iroquois waters laved the 

 ice-front, then some vertical spacing of the bars would have continued 

 northward to the Covey outlet. Any uplift, even after Covey Pass was 

 opened, would have thrown the outflow back to Rome and still produce 

 splitting of beaches at Covey. The figures appear to prove two things — 

 a wave uplift subsequent to the ice-retreat and the total uplift value of 

 the isobases in the map. 



The Canadian points, measured by Professor Coleman, lie in about the 

 same isobasal belt as Watertown and exhibit similar movement, but show 

 less Glacial uplift, evidently because of the longer halt of the glacier over 

 the Ottawa lowland and the belated uplift (125, plate 17). Evidence 

 has already been given to show that Quays did not rise at all until after 

 it was immersed in Iroquois water. 



Second, as to the dimensions of the earth wave. While the Watertown 

 district was rising, the Iroquois water level appears to have been com- 

 paratively stationary. Any considerable rise at Covey outlet would have 

 thrown the outflow back to Rome, in which case lower bars would have 

 been formed in the Covey district, inferior to the Covey outlet. It ap- 

 pears, therefore, that the district of rapid wave uplift must have been 

 limited by the distance between the two outlets. The distance between 

 the Rome and Covey isobases is 142 miles. North of Malone there was 

 very little uplifting, which cuts off about 17 miles. This leaves a breadth 

 transverse to the earth wave of 125 miles. The Canadian data are at 

 present supplied by only a relatively small area in the district of Trent 

 River, which seems to represent the north slope of the earth wave, and 

 thus correlating with the Malone-Covey district. 



Parallel with the ice border the wave might have indefinite extent, and 

 no facts are at hand relating to that. 



The height of the earth billow at Watertown — that is to say, the uplift 

 in excess of any synchronous rise of the Iroquois water level — is not over 

 70 feet. With a horizontal amplitude of 100 to 125 miles, this vertical 

 movement may be regarded as a very moderate undulation of the earth's 

 zone of rigidity, and as far within the possible theoretic limits. 



It seems probable that the earth wave, of the sort here discussed, was 

 only the beginning of the uplift movement, merely the first effect of the 

 local relief of pressure, and that it was promptly succeeded by or resolved 

 into a general lifting movement that involved the whole depressed area 



