CHAPTER XVI. 



ALPINE AND ARCTIC PLANTS IN CONNECTION 

 WITH GEOLOGICAL HISTORY. 



THE group of the White Mountains is the culminating point 

 of the northern division of the great Appalachian range, extend- 

 ing from Tennessee to Gaspe' in a south-west and north-east 

 direction, and constituting the breast bone of the North Amer- 

 ican continent. This great ridge or succession of ridges has 

 its highest peaks near its southern extremity, in the Black 

 Mountains ; but these are little higher than their northern 

 rivals, which at least hold the undisputed distinction of being 

 the highest hills in north-eastern America. As Guyot 1 has 

 well remarked, the White Mountains do not occur in the general 

 line of the chain, but rather on its eastern side. The central 

 point of the range, represented by the Green Mountains and 

 their continuation, describes a great curve from Gaspe to the 

 valley of the Hudson, and opposite the middle of the concave 

 side of this curved line towers the almost isolated group of the 

 White Hills. On the other side is the narrow valley of Lake 

 Champlain, and beyond this the great isolated mass of the Adi- 

 rondack Mountains, nearly approaching in the altitude of their 

 highest peaks, and greatly exceeding in their geological age, the 

 opposite White Mountain group. The Appalachian range is 

 thus, in this part of its course, supported on either side by out- 

 liers higher than itself. The dense grouping of mountains in 

 this region is due to the resistance offered by the old Adiron- 



1 Sillimaris Journal. 

 425 



