THE ENJOYMENT OP NATURE. 13 



the Cinchona, whose fever-healing bark is deemed the more 

 salutary the more often the trees are bathed and refreshed by 

 the light mists which form the upper surface of the lowest 

 stratum of clouds. Immediately above the region of 

 forests the ground is covered with white bands of flower- 

 ing social plants, small Aralias, Thibaudias, and myrtle- 

 leaved Andromedas. The Alp rose of the Andes, the mag- 

 nificent Befaria, forms a purple girdle round the spiry 

 peaks. On reaching the cold and stormy regions of the 

 Paramos, shrubs and herbaceous plants, bearing large and 

 richly-coloured blossoms, gradually disappear, and are suc- 

 ceeded by a uniform mantle of monocotyledonous plants. 

 This is the grassy zone, where vast savannahs (on which 

 graze lamas, and cattle descended from those brought 

 from the old world) clothe the high table lands and the 

 wide slopes of the Cordilleras, whence they reflect afar a 

 yellow hue. Trachytic rocks, which pierce the turf, and rise 

 high into those strata of the atmosphere which are supposed 

 to contain a smaller quantity of carbonic acid, support only 

 plants of inferior organization Lichens, Lecideas, and the 

 many-coloured dust of the Lepraria, forming small round 

 patches on the surface of the stone. Scattered islets of 

 fresh-fallen snow arrest the last feeble traces of vegetation, 

 and are succeeded by the region of perpetual snow, of 

 which the lower limit is distinctly marked, and undergoes ex- 

 tremely little change. The elastic subterranean forces strive, 

 for the most part in vain, to break through the snow-clad 

 domes which crown the ridges of the Cordilleras ; but even 

 where these forces have actually opened a permanent channel 

 of communication with the outer air, either through crevices 

 or circular craters, they rarely send forth currents of lava, more 



