CHINA, MONGOLIA, AND JAPAN. 69 



Through this broad tract two minor valleys are indicated, one in the trough that 

 contains the Aralo-Caspian depression and the lakes of the Barabinsky steppe, and 

 the other containing the Kara sea, the White sea, the lakes of Finland and the 

 Baltic. 



Beyond the mountains of Norway the great depression occupied by the Sea of 

 Greenland and the North Atlantic, is one of the best defined in this series of valleys. 



Finally, in the vast extent of lowlands of British America we have a great geo- 

 clinal depression lying between the Appalachians and the Rocky mountains, forming 

 an elevated geoclinal valley between N. E. and N. W. systems of elevation; just as 

 in the North Pacific Ocean we have a depressed valley of the same kind between 

 N, W. and N. E. systems — the Rocky mountains and the Sinians. 



Both Prof. Guyot and Prof. Dana have demonstrated the fact that the principal 

 continental outlines are referable to N, E. and N. W. systems of trends. 



