244 H. L. FAIRCHILD PLEISTOCENE UPLIFT OP NEW YORK 



The table, plate 11, gives examples of the above analysis. Comparison 

 of this table with the map of isobases brings out clearly some very inter- 

 esting and important data. It appears that Hamilton, Ontario, at the 

 extreme west end of Lake Iroquois, received during Glacial time more 

 than half of its total uplift. The same is true of Eome, the southeastern 

 extremity of the lake and the main outlet; and these two points, Eome 

 and Hamilton, were the first to be relieved of the ice burden. At Lewis- 

 ton the glacial uplift was just half the total, while between Lewiston and 

 Eome, the most southerly stretch of the Iroquois shore, but somewhat 

 longer beneath the ice load than the east and west points, the glacial 

 uplift was less than the post-Iroquois rise. It will be seen that Eome 

 was the point of largest Glacial uplift and of the lowest initial altitude. 

 From Eome northward the Glacial uplift was small, declining to zero near 

 the Canadian boundary, where all the rise seems to have taken place after 

 the marine level was established in the Saint Lawrence Valley. 



These figures appear to prove that the New York area did not rise as 

 a rigid body, but that the uplifting was a wavelike movement, following 

 the removal of the waning ice-sheet, as long ago suggested by Upham 

 (31). 



The low initial attitude of Eome agrees with the requirement for the 

 early glacial drainage, for the earliest ice-border streams in central New 

 York passed east to the Mohawk-Hudson by channels at Syracuse which 

 today, after uplifting and Iroquois silting, are less than 400 feet above 

 tide (115, 119). The Schenectady- Albany district was beneath the sea 

 down to much later time, though some uplift occurred in Iroquois time, 

 as proved by directions of Iromohawk flow beyond Schenectady, described 

 by J. H. Stoller (112). 



The tabulated data studied in connection with the map shows that dif- 

 ferent portions of the large area had different up-movements. About the 

 east end of the Ontario basin the post-Iroquois uplift was steepest in a 

 northerly direction, due to the later and more rapid rise of the Canadian 

 area. This partly accounts for the steep gradient on the Iroquois shore 

 north of the fulcral line. 



In applying the mathematics of the table to any particular locality it 

 must be understood that the figures apply to the particular point taken 

 for Iroquois or for marine altitude ; for example, the figures for Hamilton, 

 Ontario, are for the summit of the Iroquois bar. The initial altitude of 

 the city of Hamilton would be calculated by comparison of its altitude 

 with the summit of the great gravel ridge of Iroquois. Eome is a more 

 complex example. The altitude taken is the crests of the beaches south- 

 west of the city — 460 feet. The lowest part of the col or wasteweir of 



