40 



NORTH A:\rERI('AN FAUNA. 



These dwarf groves oiler atti-aetive slielters from wind and storm, 

 and we nsnally camped among tliem when working the upper sh)pes. 



The tree is one of exceptional hardihood, and as it pushes on still 

 farther into the realm of eold the trunks become completely prostrate 

 and the branches luig the ground, forming among the rocks dense mats 

 which sometimes rise a foot or two above the general level, but at their 

 upper limit usually occu])y depressions, or, if growing in the lee of a 

 bowlder, crouch behind it and continue its surface level to the adjacent 

 slope, as if trimmed to tit. Indeed, one is amazed at the way these 

 uppermost ])iues avoid exposure by tiatteniug themselves into the hol- 

 lows, as if afraid to lift a finger above the general level. Their life is a 

 perpetual struggle — not against competing plants, but against a hostile 

 environment. In summer they are buffeted by the winds ami pelted by 

 sand and gravel; in spring they are swept and torn ])y the resistless 

 avalanches, and in winter they are deejjly buried under heavy banks of 

 snow. The prostrate trunks in young and middle-aged healthy trees 

 are completely concealed, often half covered by stones and pumice sand, 

 and hidden by the density of their own branches and foliage ; but in very 

 old trees, and those injured by passing avalanches or laid bare by the 

 washing away of i)rotecting rocks during violent storms, the trunks are 

 partly exposed and their extraordinary features may be easily examined. 

 As a rule they are not only nalced, but the strongly twisted wood, 

 gnarled, contorted, and, ironlike in firmness, has been eaten into by 

 the sand blast till the knots and hardest parts stand out in prominent 

 ridges. 



A little below tiraberline on the north side of Shasta, between Xorth 

 Gate and Shastina, is an extensive gently sloping pumice i)lain, strewn 

 with fragments of gray shaly lava, and thickly sj^otted with rather 





;-*^v^ 





. r- -■»/ 





Fig. 22.— Puinif-r |il:iiii ikhiIi Midc of Sliasta, showiiiL; liiiil" i lun- m.iis nl W liilc li:irk jiiiios. 



large mats of pines, averaging 1^ to 1 feet in height, whicli give a most 

 curious aspect to tin; region (tig. 1^2). This area, which is about a mile 



