228 J. W. SPENCER POSTGLACIAL EAKTH-MOVEMENTS 



north-northwest and the zones of equal rise become somewhat parallel to 

 the direction of the Saint Lawrence Paver, as might be expected from 

 the change of course of the "height of lam"' -« shown on the map), to 

 which the isobars are parallel farther southwestward. 



Beyond the locality where the beaches can be triangulated, the same 

 amount of deformation is observed in the marine beds at Montreal and 

 those on the northeast flanks of the Adirondacks mass. These diminish 

 in height on proceeding farther south, as shown by TVoodworth. who 

 finds that they do not extend beyond the head of the Champlain Valley. 



The measured earth-movements, aggregating 540 feet between the 

 head of Lake Ontario and Parishville. have occurred since the birth of 

 Xiagara Fal- ; — rars ago. Parr of the deformation has taken 



place within 3.500 years, but for a period of over a half a century we 

 have definite physical proof that there have been no earth-movements in 

 the lake regions. 



