CONCLUSION AND SUMMARY 255 



the true vertical interval throughout the whole area reached by the sea- 

 level waters. 



Making use of this fixed vertical difference in height of 290 feet in 

 connection with the isobases of total uplift, a table is compiled (plate 11) 

 which for any point where either the Iroquois or the sealevel altitude is 

 known gives us (1) the amount of uplift during glacial time — that is to 

 say, all the time preceding the death of Iroquois; (2) the amount of post- 

 Iroquois (post-Glacial) uplift; (3) the initial altitude of the point before 

 any uplift occurred; and (4) the amount of flooding at any point by the 

 excess uplift of the rising outlet at Eome. 



The data of the table also show (1) that the greatest amount of glacial 

 uplift was in the districts that were the earliest relieved from the burden 

 of the ice-sheet; (2) that the most northerly districts reached by Iroquois 

 waters did not rise at all until after Iroquois time — that is, until the 

 sealevel waters were admitted into the Ontario basin; (3) that the split- 

 ting of beaches into vertical series of bars is restricted to land north of 

 the Eome isobase, which rose by a wave movement before the extinction 

 of Iroquois and probably after the outlet was shifted to Covey Pass, and 

 the rising of the lake surface ceased; and (4) that the series of multiple 

 bars or split beaches disappear northward, but that all have been uptilted 

 together, as a unit, by the post-Iroquois uplift. The data also imply that 

 no land uplifting took place at any locality while the ice-body lay over it. 



The facts prove, what has been assumed by students of the subject, that 

 the uplifting of this part of the continent, following glaciation, was not 

 as a unit or a rigid mass, but by a wave movement as of a slowly bending 

 crust. 



Students of the large problem of diastrophism should seek the data for 

 extending the isobasal lines to inclose the area of Pleistocene uplift, and 

 they should not be repelled because the data indicate a greater submer- 

 gence during glacial time than has been supposed. 



Following this trail, the workers in Canada should look for the sealevel 

 beaches and other shoreline phenomena at the elevations given in the 

 table, remembering that the features are likely to be weak in most locali- 

 ties, being formed on a shore that was rapidly lifting; but that a few 

 positive occurrences of shore phenomena outweigh any quantity of nega- 

 tive results. 



Bibliography 



The titles in the following list are of papers which bear more or less 

 directly on the evidence and work of the Pleistocene waters, g]acial and 

 marine, in the Ontario-Saint Lawrence, Champlain-Hudson, and Con- 



