On the Importance of Geological Information, Sj-c. 131 



a great deal of valuable information, connected with the scientific 

 knowledge of the surface of country, might be collected from 

 officers on service, without exposing the government to any ma- 

 terial expense. 



The study of chains and ranges of mountains, forms at this time 

 a most interesting branch of geology. It would seem that all 

 the great inequalities of the earth's surface, which have not been 

 formed by the action of excavating waters, owe their origin to 

 an expansive subterranean power, which has thrust them up 

 through ancient surfaces. During the present era, mountains 

 have been formed in this manner, both from the sea and land. 

 In the year 1538, Monte Nuovo, in the bay of Naples, was thus 

 thrown up through the water, in one night, to the height of 

 four hundred and fifty feet; and in Mexico, in 1759, a tract of 

 land, from three to four sqtiare miles in extent, was upraised, to- 

 gether with the cone or peak of Jurullo. The mass in its most 

 convex part is five hundred and twenty-four feet above the old 

 level, and its celebrated peak Jorullo, is 1695 feet high. The rock, 

 constituting the old level, was a base of green-stone, with porphy- 

 ry, basalt, &c. It is evident from a very careful consideration of 

 geological phenomena, that all the mountain ranges, with the ex- 

 ceptions before made, have been formed by that sort of subter- 

 ranean action, which has produced Monte Nuovo and Jorullo. 

 All mountains, then, have come up through other beds, and have 

 necessarily dislocated them, and laid them upon their flanks at 

 high angles. In various parts of the world, we find mountains 

 thus situated, and without any horizontal deposits lying upon the 

 edges of the ancient disturbed beds ; whence, we are authorised 

 to infer, that the epoch of their upraising is comparatively recent, 

 and posterior to the last deposits.* In Leicestershire, England, 

 the granite, b, b, and slate, c, c, of Charwood forest,f exist in 

 beds highly inclined ; but on the edges of those beds, new red sand- 

 stone, a, a, and lias, e, are found in a horizontal position ; proving 

 that these last have been deposited subsequent to the upraising 

 of the first. We thus infer, that those primitive beds, were par- 

 tially raised in the ocean ; and that at a subsequent period, the 

 secondary rocks were deposited upon them, marking two distinct 

 geological epochs. On the other hand, the system of mountains, 



♦ This is a safe conclusion in casrs where no presumption exists of beds, superin- 

 cumbent upon them in the series, being absent from particular causes, 

 r Plate 4, fig. 2. 



