286 A VISIT TO THE PROVINCES 



the map will afford the reader. Their poverty hitherto, and that of all nature surrounding 

 them, will ever remain as ohstacles to prevent extensive or very remunerative operations. 



As will have heen seen from its export trade, the province of Coquimho ranks among the 

 most productive copper districts of the world ; and, were there suitahle machinery and skilful 

 mining engineers, the more precious metals would he obtained in amply remunerative quantities. 

 The entire region embraced between the parallels of 30 and 31 south, and the 73d and 74th 

 degrees of longitude, is literally crowded with veins of gold, silver, quicksilver, copper, and 

 other most rare combinations of metals. Only one or two of them, at which remarkable min- 

 erals have been found, will even be named. The reader must refer to the map for the locali- 

 ties, and to the accompanying report of Prof. Smith for an account of the ores produced, and 

 the characteristics of many others. It will be well to bear in mind, too, that as we progress 

 southward, mines exist in a more hospitable region ; water and fuel, the two primary necessities, 

 become abundant ; and with the first there are consequently increased alimentary resources. 



The mines which merit more than a passing reference are those of Arqueros and Algo- 

 dones one situated to the north and the other to the south of the Coquimbo river. The 

 former lie thirteen leagues N.E. of La Serena, and nearly at an equal distance from the coast, 

 at the contact of the porphyritic and dioritic masses constituting the base of the littoral region 

 with the secondary stratified formation. They were accidentally discovered, in 1825, by one of 

 the wood-hunters of the province stumbling over rolled stones containing a large per-centage 

 of native silver, and which were uselessly cumbering the bottom of a ravine. As might be 

 supposed, a crowd went to the spot when his good luck became known ; and it is said that 

 $10,000 worth of silver was picked from the surface in ores of this nature. In a short time, 

 not only the vein from which these stones came was discovered, but also two others, lying 

 nearly parallel with it ; since when their combined products have realized more than four mil- 

 lions of dollars. The hill is not far from a league in diameter. Says Prof. Domeyko: 



"Starting from the Bay of Coquimbo for Arqueros, we leave the granite and sienite at the 

 shores of the Pacific, and traverse the amphibolic porphyries and diorites, in which we perceive 

 the copper mines of Brillador, the gold mines of Santa Gracia, and many veinules of gold and 

 copper of little importance. It is only at a league from Arqueros that we observe the layers 

 of the stratified formation strongly marked ; and at that very locality we find the mines of 

 Kodaito and Komero, containing metallic silver and chlorite ore. 



"The layers which here compose the system of stratification are banks of conglomerates, 

 tufa, and porphyritic breccia, alternating with thin compact schistous and sometimes calcareous 

 beds. One of the last, entirely composed of shells,* is found between the mines of Rodaito 

 and Arqueros, on the road leading to the latter. 



"Now this system of stratified rocks of Eomero and Rodaito rests on felspathic masses, 

 deprived of amphibole, which form the most elevated plateau of the mountain of Arqueros. 

 Arrived at its summit, which, according to the observations of M. Gay, is 4,800 feet above the 

 level of the sea, and casting an eye over the surrounding country, we perceive the escarpments of 

 the stratified formation extending from W. to S.E. ; and, as they indicate the boundaries of 

 the upraised formations, one would say that the felspathic mass which has pierced them, and 

 encloses within it here the great riches of Arqueros, forms the centre of a local sublevation. 



"As we turn from S.W. to N.E., the mass changes its aspect. At first it is a green material 

 (pate), containing lamellar white and reddish felspathic crystals, or rather compact amorphous 

 parts of the same nature as the crystals. It often becomes reddish or bluish gray, without 

 change of color in the crystals. Sometimes the crystals disappear, and the rock becomes breccia- 

 form, composed of reddish and bluish portions. In short, the main body of the mountain, 



"These are bivalves very elongated, the species of which it has been impossible for me to determine. There has likewise 

 been found in it a small gryphite, which I have also met with in the silver mines between Agua Amarga and Huasco." Annales 

 des Mines, 3d scries, Vol. XX. 



