MINES, HOW DISCOVERED. 231 



in this country are generally harder than the surrounding strata ; hence, 

 during the gradual wear of the hills, they project above the surface 

 of the ground. Secondly, almost every labourer, especially in the 

 northern parts of Chile, understands something about the appearance 

 of ores. In the great mining provinces of Coquimbo and Copiapo, 

 firewood is very scarce, and men search for it over every hill and dale ; 

 and by this means nearly all the richest mines have there been dis- 

 covered. Chanuncillo, from which silver to the value of many hundred 

 thousand pounds has been raised in the course of a few years, was 

 discovered by a man who threw a stone at his loaded donkey, and 

 thinking that it was very heavy, he picked it up, and found it full of 

 pure silver : the vein occurred at no great distance, standing up like 

 a wedge of metal. The miners, also, taking a crowbar with them, 

 often wander on Sundays over the mountains. In this south part of 

 Chile, the men who drive cattle into the Cordillera, and who frequent 

 every ravine where there is a little pasture, are the usual discoverers. 



March loth. As we ascended the valley, the vegetation, with the 

 exception of a few pretty alpine flowers, became exceedingly scanty ; 

 and of quadrupeds, birds, or insects, scarcely one could be seen. 

 The lofty mountains, their summits marked with a few patches of 

 snow, stood well separated from each other ; the valleys being filled 

 up with an immense thickness of stratified alluvium. The features in 

 the scenery of the Andes which struck me most, as contrasted with 

 the other mountain chains with which I am acquainted, were, the flat 

 fringes sometimes expanding into narrow plains on each side of the 

 valleys, the bright colours, chiefly red and purple, of the utterly bare 

 and precipitous hills of porphyry, the grand and continuous wall-like 

 dikes, the plainly-divided strata which, where nearly vertical, formed 

 the picturesque and wild central pinnacles, but where less inclined, 

 composed the great massive mountains on the outskirts of the range, 

 and lastly, the smooth conical piles of fine and bright-coloured detritus 

 which sloped up at a high angle from the base of the mountains, 

 sometimes to a height of more than 2,000 feet. 



I frequently observed, both in Tierra del Fuego and within the 

 Andes, that where the rock was covered during the greater part of the 

 year with snow, it was shivered in a very extraordinary manner into 

 small angular fragments. Scoresby* has observed the same fact in 

 Spitzbergen. The case appears to me rather obscure: for that part 

 of the mountain which is protected by a mantle of snow, must be less 

 subject to repeated and great changes of temperature than any other 

 part. I have sometimes thought, that the earth and fragments of stone 

 on the surface, were perhaps less effectually removed by slowly 

 percolating snow-waterf than by rain, and therefore that the appearance 



* Scoresby's " Arctic Regions," vol. i., p. 122. 



f I have heard it remarked in Shropshire, that the water, when tha 

 Severn is flooded from long-continued rain, is much more turbid than when 

 it proceeds from the snow melting on the Welsh mountains. D'Orbigny 

 (torn, i., p. 184), in explaining the cause of the various colours of the rivers 



