242 Outlines of Geology. 



merous to particularize, upon the north as well as the south side 

 of Cornwall, derives its grandeur and charms from the various 

 assemblages of slaty headlands, promontories, creeks, and islands. 

 Sometimes its strata jet out in bold fantastic forms upon the ocean, 

 and sometimes gradually shelve away into gentle slopes ; their 

 verdure is usually scanty and uncertain, but here and there, a 

 clayey soil finds a resting-place, and cherishes patches of shrubs 

 interspersed with trees of loftier growth, and attracting the travel- 

 ler^ attention by the sterile and fragmented surface which gene- 

 rally surround these insular spots of vegetation. The beauties 

 of the coast of Cornwall are singularly contrasted by the barren 

 exterior of its central road and great mining district, where we 

 scarcely find a blade of grass to relieve the black and sombre 

 hues of the ground, but where heaps of rubbish, that once was rich 

 in embowelled treasures, give a gloomy irregularity to the sur- 

 face, and where the ponderous heaving of machinery raises sub- 

 terranean rivers to a level not their own, and turning them into 

 new channels, enables the miner to arrive at those riches, which, 

 but for the inventive genius of Watt, would have remained in 

 inaccessible obscurity. 



I have adverted to the confusion which has prevailed in the 

 definitions of grauwacke, and have endeavoured, as far as con- 

 cerns ourselves, to attain perspicuity by limiting the extent of this 

 term. Of its unlimited application I can give no better instance 

 than is furnished by the county of Cornwall, where all the slate 

 has been by some geologists, and those of experience and obser- 

 vation, classed under that embarrassing and perplexing term; 

 while others have entirely denied the existence of even a solitary 

 cabinet-specimen in the whole district. Truth, however, lies be- 

 tween these extremes, and there are, in several parts of Cornwall, 

 but more especially about the neck of the Lizard Promontory, 

 certain strata, or, as they rather should be called, beds, of a rock, 

 to which even a sceptic as to its existence elsewhere cannot deny 

 the name : it is a rock which is slaty in its composition, and slaty 

 in its texture, but which, from the fragments and particles dis- 

 tinctly embedded in the main mass, is legitimately allied to the 



