Science, Geology and Physics 



the relief features of the surrounding region. The point of dis- 1908 

 charge was at Rome, New York, as long as the barrier blocked 

 the regions north of the Adirondack Mountains. As soon as 

 the encroaching warmth of the south had removed this barrier 

 to the level of the Rome outlet, the water began flowing by the 

 St. Lawrence course. True the first outlet was not the same as 

 the present one; but it must have been many times shifted in the 

 course of the retreat of the ice. As a result of this alternate 

 shifting, together with the changing of the level of the lake, there 

 are to be found the markings of numerous shore lines, some of 

 which pass under the present level of the waters. 



These different variations must of necessity have had a great 

 effect on the work of Niagara River. When the Niagara began 

 to flow, instead of its terminal being nearly seven miles from the 

 escarpment, it was only between one and two miles away, and 

 the surface of the lake was about seventy-five feet higher than 

 now. While the outlet remained at Rome, the eastern end of 

 the lake was continually rising, which caused the waters at the 

 western end to rise over one hundred feet. This placed the shore 

 of Ontario almost at the foot of the beautiful cliff at Queenston 

 and Lewiston. After having occupied this position for a long 

 period, the surface of the waters again fell over two hundred 

 feet, carving an old shore line which is now submerged. After 

 this, various changes of level in the land and shiftings of the ice 

 barrier caused numerous old shore lines to be faintly carved. 

 These changes continued until the present outlet was established 

 and the waters began to flow along the present course of the St. 

 Lawrence. 



One might think that with these changes all the variable factors 

 of our problem have been discussed; but these same factors also 

 had their effect upon the upper lakes. In a study of the old 

 markings of all the lakes of this region, it seems that the northern 

 shores were continually rising; this, of course, points to an occu- 

 pation of a more northerly position by the lakes than at present, 

 and also a laying bare of northern parts, and shifting of waters 

 south, or possibly both of these changes at once. 



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