65 



the petrified teeth or bones of animals;, coloured 

 by metallic vapours, I have thought proper to 

 mention them here, as they are placed by many 

 among the precious stones. The turquoises of 

 Copiapo are usually of a greenish blue, some, 

 however, are found of a deep blue, which are 

 very hard, and known by the name of the tur- 

 quoises of the old rock. 



Mixed stones, of those formed by the combi- 

 nation of several heterogeneous substances, are 

 here, as elsewhere, the most numerous, and form 

 a considerable portion of the Chilian moLuitains. 

 Beside the common stones of this class, various 

 kinds of porphyry and granite of the first qua- 

 lity arc constantly met with ; and the skirts of 

 the mountains bordering the high road across 

 the Andes to Cujo, consist wholly of red, green, 

 black, and other coloured porphyries. Among 

 these is one which deserves particular attention ; 

 it is yellow, spotted with red and blue, and from 

 its being found in the neighbourhood of the river 

 Chili, I have given it the name of saxur-i 

 Chllense. 



In the plains near the coiifluence of t-ie Rio- 

 claro, a large quarry of brovrU porphyry with 

 black spots has been discovered. It ii disposed 

 in strata of two feet broad and four incbef, thick, 

 a proportion M'hich hitherto has been found inva- 

 riable ; and notwithstanding the layers arc fre- 

 quently broken by crevices or some foreign sub- 



VOL. I. F 



