282 APPENDIX. 



8. Above the line of perpetual snow, 

 the cold is occasionally so much dimi- 

 nished, that a few plants of Ranunculus 

 glacialis, and other similar ones, may now 

 and then be found, in the clefts of some 

 dark rock rising through the snow. This 

 happens even to the height of 500 feet 

 above that line. Further up the snow is very 

 rarely moistened. Yet some umbilicated 

 Lichens (Gijrophora), &c., still occur in 

 the crevices of perpendicular rocks, even 

 to the height of 2000 feet above the line 

 of perpetual snow. These are the utmost 

 limits of all vegetation, where the mean 

 temperature seems to be + 1,"1 of Celsius 

 (30 of Fahrenheit). The Snow Bunting, 

 Emberiza nivalis, is the only living being 

 that visits this elevated spot. 



