CHAPTER V 

 THE NORTH TEMPERATE ZONE— Concluded 



THE ROCKY MOUNTAINS AND PACIFIC SLOPE 



The main range of the Rocky mountains extends from New 

 Mexico to northwestern Montana, and thence into the Canadian 

 northwest. 



There are two pretty well marked regions which differ a good 

 deal in character. The highest summits are in the southern 

 part of the range, several peaks in Colorado, e. g., Pike's Peak, 

 Long's Peak, exceeding 14,000 feet, but the mountains are far less 

 abrupt than further north. In northern Montana and Canada, 

 the main range is very much broken up, with very steep slopes 

 and sharp peaks, but none of the latter attain the altitude of 

 those further south. 



The national parks in Colorado, Wyoming and Montana, 

 make the Rocky Mountains very accessible, so that the floras 

 of these interesting regions can be easily studied. 



The country near Denver, and in Estes Park, illustrates very 

 well the more salient features of the southern or Park region 

 of the eastern Rockies. 



As one approaches the mountains in Colorado, the prairies 

 of Kansas and Nebraska merge into a semi-arid region of bunch- 

 grasses interspersed with xerophytic types* reminiscent of the 

 true deserts of the south and west. This plain has an elevation 

 of about 5,000 feet, and in places, the foot-hills form sloping 

 table-lands or " mesas, ,: which are often traversed by streams 

 descending from the mountains. 



The western edge of the mesa is both more sheltered and 

 better watered than the eastern side, which slopes into the dry 

 grass-land of the great plains. The vegetation of the western 

 edge of the mesa is of a somewhat mixed type. There is sufficient 

 moisture to permit the growth of a few conifers and aspens, 

 and a number of shrubs and herbaceous species occur which 



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