MINERALS OF CHILE. 55 



side, where the upheaving force appears to have concentrated 

 all its energy, the slopes are abrupt, and transformed frequently 

 into vertical precipices of considerable height. The mountains 

 appear heaped confusedly one on top of the other, and the first 

 impression is that in the midst of so much confusion it is vain 

 to seek for the primitive condition of the surface of Chile. 

 Stratified rocks disappear entirely from north to south for the 

 mean width of forty -five miles — from the desert of Atacama to 

 Yaldivia. These rocks, although they once existed, are now 

 profoundly altered or entirely melted by contact with the 

 enormous masses of granite. The clay-shales, which doubt- 

 less constituted the mass of the original stratified rocks, are 

 now transformed into porphyries of every shade and of the 

 most varied composition, alternating in some parts with beds 

 of compact quartz. Even when the rocks are seen stratified, 

 far removed from the masses of granite, and in beds sensibly 

 horizontal or little inclined, still the numerous injected veins 

 which traverse them and ramify in all directions prove that 

 hardly any where have the rocks escaped the modifying force 

 of igneous action. 



Two immense granite elevations appear to have disturbed 

 Chile in its entire length parallel to the coast. One is imme- 

 diately on the coast, with an average breadth of forty-five 

 miles, while the other is one hundred miles east in the midst 

 of stratified rocks. The first range plunges into the sea, hav- 

 ing valleys in various parts of it filled with tertiary deposits. 

 As regards the respective ages of these two ranges there ap- 

 pears to be a difference of opinion ; some supposing that the 

 range on the coast was first upheaved, and at a subsequent 

 period the inner range, while others suppose them to have 

 originated at the same time. But whichever one of these 

 suppositions is true, the general characters of the rock of the 

 two ranges are the same, as well as the metalliferous veins 

 and accompanying vein rocks. Associated with the granite 

 of these ranges are hornblende rocks of the greatest variety, 

 porphyries of all shades, containing crystals of feldspar some- 

 times of considerable size. Besides these, there are other 

 compact rocks which can not be properly classified. 



The principal masses of secondary rocks that lay between 

 the two ranges of mountains are composed of metamorphie 



