ferent species, will, in a short time, enable the most 

 common observer to distinguish them. 



The highest mountains in these islands, and in- 

 deed in the whole of the old continent, are constituted 

 by granite; and this rock has likewise been found at 

 the greatest depths to which the industry of man has 

 as yet been able to penetrate; micaceous schist is often 

 found immediately upon granite; serpentine or marble 

 upon micaceous schist: but the order in which the 

 primary rocks are grouped together is various. Mar- 

 ble and serpentine are usually found uppermost; but 

 granite, though it seems to form the foundation of the 

 rocky strata of the globe, is yet sometimes discovered 

 above micaceous schist. 



The secondry rocks are always incumbent on the 

 primary; the lowest of them is usually grauwacke: up- 

 on this, limestone or sandstone is often found; coal 

 generally occurs between sandstone or shale; basalt 

 often exists above sandstone and limestone; rock salt 

 almost always occurs associated with red sandstone 

 and gypsum. Coal, basalt, sandstone, and limestone, 

 are often arranged in different alternate layers, of no 

 considerable thickness, so as to form a great extent of 

 country. In a depth of less than 500 yards, 80 of 

 these different alternate strata have been counted. 



The veins which afford metallic substances, are 

 fissures more or less vertical, filled with a material 

 different from the rock in which they exist. This 

 material is almost always crystalline; and usually con- 

 sists of calcareous spar, fluor spar, quartz, or heavy 

 spar, either vSeparate or together. The metallic sub- 



