PLATE 15 

 Late Tertiary and Quaternary Tectonic Map 



Red, besides denoting volcanic rocks, shows laccolithic clusters in the Colorado 

 Plateau. Numerous centers of volcanism throughout the Basin and Range 

 province are not shown. The blue color extends to lines of maximum trans- 

 gression of seas during the time represented by the map. Hudson Bay and 

 St. Lawrence submergence pre-dates the post-glacial uplift. The submerged 

 coastland of British Columbia has been uplifted 600 feet in post-glacial time. 

 See Fig. 31.25 for regional vertical movements of the western Cordillera in 

 late Cenozoic time. 



