GEOLOGIC TIME. 



655 



DESCRIPTION OF MAP. 



On the^map the hypothetical areas of the Cordilleran, Mississippian and Appa- 

 lachian seas are clearly indicated. The land area west of the Cordilleran sea is 

 numbered No. 1. The Californian sea and the area of Paleozoic deposits of western 

 British Columbia No. 10. The northern extension of the Cordilleran sea (No. 9) is 

 continued as the Paleozoic-devonian sea to the Arctic ocean. The early Cambrian 

 land area (No. 2) east of the Cordilleran sea must have been more or less covered by 

 water during later Paleozoic time. The area now covered by Mesozoic deposits, 

 indicated by No. 3, was presumably covered by the westward and northward extension 

 of the Paleozoic-Mississippian sea. The area east of the Appalachian sea is indicated 

 by No. 4 ; and the supposed land barrier between the Hudson Bay and the Mississip- 

 pian sea by No. 6 ; it is not improbable that during Ordovician or Silurian time a sea 

 may have connected the two latter seas. The region to the south, indicated by No. 5, 

 is supposed to have been covered by the southward extension of the Appalachian, Mis- 

 sissippian and Cordilleran seas. It is now covered by deposits of Mesozoic and 

 Cenozoic seas. 



A more detailed description of the map can be gained from the section on the 

 growth of the continent and on the geographic conditions accompanying the different 

 depositions of Paleozoic sediments in the Cordilleran sea. 



