M. Mohs on the Discovery of Useful Minerals^ 340 



be able to form a sufficiently accurate opinion of their form 

 and other relations. 



When the new mountain-mass has been examined in all the 

 particulars which have been pointed out, we advance farther, 

 and conduct our investigation of the next mountain-mass in 

 the same manner. We proceed in this manner until we at- 

 tain the high mountain-ridge, regarding whose relations we 

 had already made ourselves pi-eviously acquainted. The other 

 declivity of the valley is then to be investigated, probably from 

 above downwards, and we may rest assured, when all this has 

 been carefully observed, we have done every thing that could 

 be done, so far as we have gone, in a search of this kind. The 

 phenomena of stratification with which we have become ac- 

 quainted in the first transverse valley, will lead us to decide 

 if we should, in the mean while, pass over one or several of 

 the neighbouring valleys, and dbect our attention to a more 

 remote one, which is probably distinguished from the others 

 by its position and constitution, or if we should investigate 

 them in the order of their sequence. 



If we have found, in the valley that has been investigated, 

 that the stratification on the two sides is extremely regular, 

 and if we have seen that the structiu-e of the mountain-masses 

 on the lai-ge and the small scale, is parallel to the surfaces 

 of superposition, and that it is as perfect a plane as can be 

 expected in such circumstances, we may, with some reason, 

 presume, that these relations suffer no essential change in ad- 

 joining valleys ; and, as it is of importance to obtain a general 

 knowledge of the whole phenomena of the stratification or of 

 the constitution of the tract, it will probably be advisable to 

 pass over the neighbouring valleys on both sides, in order to 

 select valleys at a greater distance, from which we may expect 

 to be able to draw new inferences. But these adjoining val- 

 leys ought not to be entirely placed aside, and they deserve to 

 be examined with as much care as the others, for we never 

 can know that they may not lead to discoveries which could 

 not have been anticipated from what we had leai'nt in then- 

 vicinity. If, in the valley which ha*; been first examined, the 

 phenomena of stratification should be less regular, and if the 

 individual mountain-masses should appear more in irregular 



