276 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1926 
continued uptilt of the area depressed during the periods of glacia- 
tion. The earthquake history of the region affords no warrant for 
the belief that the region of the northeastern United States is to 
Sketch map to show where postglaclal faults have been observed within the glaciated region of North America. 
Of those from the Province of Quebec only a few have entered 
5 
ia. 
remain immune from destructive earthquakes. Such visitations, it 
may be assumed, will be far less frequent than earthquakes which 
occur within the great girdles where mountain growth is proceeding 
