86 THE JIINERALS OF CHILE. 



Two immense granite elevations appear to have <listurbed Chile in its entire length, jiarallel to 

 the coast. One is immediately on the coast, with an average breadth of 45 miles, while the 

 other is 100 miles east, in the midst of stratified rocks. The first range plunges into the sea, 

 having valleys in various parts of it filled with tertiary deposits. As regards the respective 

 ages of these two ranges, there appears to he a difference of opinion ; some supposing that the 

 range on the coast was first upheaved, and at a subsequent jjeriod 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, sometimes of considerable size. Besides these, there are other compact rocks, which 

 cannot be jiroj^erly classified. 



The principal masses of secondary rocks that lay between the two ranges of mountains are com- 

 posed of metamorphic porphyry, of a great variety of shades of color. Sometimes the porphyry 

 is entirely altered ; it then contains well-formed crystals of feldspar, and appears to have been 

 melted where it now rests ; and at other times it is earthy, as if the transformation has been 

 incomplete. Largo masses of reddish, yellow, and violet quartz, alternate with the porphyry, 

 in certain points; also, calcareous beds, sometimes fossiliferous. These stratified rocks are 

 elevated on the flanks of the Andes, and form some of the most prominent peaks of this 

 range. These strata are so completely pierced and elevated in every direction by the masses 

 of granite, as to modify in every possible manner their direction, inclination, and mineralogical 

 character. 



Besides the secondary stratified rocks just made mention of, there are other stratified rocks, 

 which are horizontal, having been dejjosited since the elevation of the mountain chains. They 

 are all, however, of recent origin and of small extent, disseminated along the coast, with the 

 exception of the sandy plain that extends between Huasco and Copiapo, having a length of from 

 120 to 130 miles, with a variable width. This plain has, however, been elevated since its form- 

 ation; in fact, M. Domeyko has determined three distinct terraces of successive and gentle 

 elevation. 



There are also alluvial deposits now going on in some of the valleys of the elevated portions 

 of the mountains, consisting of a fine clay, transported there by the mountain streams. 



According to the observation of M. Crosnier, he has encountered but one formation that 

 appears to be of lacustrine origin, and this is situated in the cordilleras of Chilian, 45 miles 

 north of Lavaderos. 



The tertiary deposits subsequent to the elevation of the Andes contain, in many parts, 

 lignite. Some of these places are worked. The i^rincipal mines are situated to the south of 

 Biobio, some 20 miles distant from the mouth of this river, on the sea-shore. The mines are 

 called Lota and Lotilla. 



Some of the departments of Chile have been examined with minuteness by M. Domeyko, 

 more especially that of Copiapo ; which, although little else than a vast desert, is the richest 

 department of Chile in mines of every descrijDtion, there not being a single mountain where 

 the veins are not of sufficient importance to be worked. And it is worthy of remark, that no 

 mines are found higher than 4,500 feet above the level of the sea; and this peculiarity, I 

 believe, pertains to all parts of Chile. 



Taking the Bay of Cojjiapo as a starting point, and going east, we find the underlying rock 

 of the country granite, the surface being covered with tertiary deposits of very modern origin, 

 the same that is found at the mouth of all the Chilean rivers. These deposits form two and 

 three terraces, and consist principally of sand, mixed with shell and gravel. At about six miles 

 from the sea, solid calcareous beds show themselves, containing species of crustacccB, now found 

 living on the shore. The granite of this coast is fine grained, having the same aspect as that 

 in the neighborhood of Coquimbo, and is the same as that of the mountains of Carrisal, San 



