MODE II. CLAY SLATE. 259 



argillaceous, which are however of vast extent 

 and great importance. 



The most authentic and scientific account of Andes. 

 the construction of that vast chain of mountains 

 the Andes, is contained in the travels of Helms, 

 a German mine-master, who was appointed to 

 introduce Born's method of amalgamation into 

 the Peruvian metallurgy. He remained in that 

 country from 1789 to 1793, and in 1798 pub- 

 lished his Journal, containing his daily observa- 

 tions made on the spot. In the English trans- 

 lation, or rather abridgement, the translator, 

 unaware of their consequence, has omitted many 

 important particulars; but enough remains to 

 show the construction of this magnificent and 

 singular chain, which astonished our author by 

 such abrupt irregularities, and such various al- 

 ternations of their component parts, as he had 

 never beheld in the mountains of Hungary, 

 Saxony, or the Pyrenees. In no country, he 

 adds, does a revolution of nature appear to have 

 been so general as in South America, and the 

 traces are every where discoverable. 



After further premising that he travels from 

 Buenos Ayres to Lima, across the chief region 

 of the Andes, his scattered information on this 

 important topic shall be brought before the 

 reader in one point of view. 



*f During the journey to Tucuman we found 



