10 



THE CONIFERS OF THE NORTHERN ROCKIES. 



Intel-mountain glaciers worked destruction in forests not touched 

 by the main sheet. Evidence of such glaciers is abundant through- 



FIG. 3. Near view of the trunk of the Western Yellow Pine. Tree about 3 feet in diameter; 

 young Yellow Pine in the foreground. 



out the whole region. It is probable that, some survived in advance 

 of the ice, but modifications of climate during this period must have 



