236 Russell Institution. 



Great Britain, and different parts of Europe and America, 

 were explained by drawings and sections. T|ie highest 

 point at which granite is found in Europe is 15,000 feet ; in 

 South America granite has not been observed higher than 

 1 IjOOO feet ; but in that country the granite and stale roclo 

 are covered with immense beds of porphyry and basalt, 

 which Mr. Bakewell said he was inclined to believe were 

 the products of subterranean fires. The rocks that lie next 

 to the primary have been called transition rocks, from a 

 fanciful supposition that they were formed when the earth 

 was passing from an uninhabitable to a habitable state. 

 These principally consist of particular lime rocks, and a 

 rock called by the Germans grauwacke, which is a kind of 

 coarse slate intermixed with fragnients of other rocks. 

 These lime rocks form entire mountains in Yorkshire, Der- 

 byshire, and part of North Wales. Mr. Farey, in his late 

 survey of Derbyshire, has described the undermost lime- 

 stone of that county as the lowest rock in England ; but 

 Mr. Bakewell observed, that the same limestone which 

 dips under the surface in the northern part of Derbyshire 

 rises up again in the north-west of Yorkshire, and is there 

 found to rest upon slate. In Shropshire and Wales similar 

 limestone with similar metallic veins also rests upon slate, 

 and this slate in al! probability rests upon granitic rocks, 

 though the granite is not sufficiently elevated to be seen, 

 except on the western verge of England and Wales. The 

 primary and first order of secondary rocks are the reposi- 

 tories of metallic ores. In the lime rocks of this class the 

 most extensive caverns are found, some of which were de- 

 scribed with sections, explaining their formation by subter- 

 ranean currents. Mr. Bakewell stated the influence of 

 elevated mountains on the temperature of the adjacent 

 countries, which, he observed, might in some degree be 

 measured by the period at which snow disappears froin their 

 summits. In some few instances, he said, snow had coiif 

 tinned the whole year on the summit of Crossfell in Cum- 

 berland. The influence of mountain scenery even over the 

 untutored mind was in many nations almost indelible, and 

 created a strength of local attachment which was not known 

 to exist in the inhabiiants of flat and more fertile districts. 

 The lecturer particularly recommended to the opulent in- 

 habitants of large cities, an occasional residence among the 

 mountains ; where he observed they might contemplate the 

 grand features of creation, and revive their taste for the 

 sublime beauties of nature; and from whence ihey could 

 scarcely fail to return with invigorated health, and with a 



certain 



