346 M. Molis on the Discovert/ of Useful Minerals. 



shapes {stockartigen gestal(en) than in beds, being sometimes 

 of a greater, sometimes of a smaller extent, and should not 

 present relations corresponding to a normal stratification, the 

 necessitjr of ascertaining the connection of the masses and the 

 actual nature of the arrangement, would cause us to examine 

 the adjoining valleys, and not only to do so with the care be- 

 stowed on the first valley, but to prosecute our investigations 

 respecting the real nature of the phenomena, until no doubt 

 should remain on the subject, and until we should be able to 

 delineate them without fear of error on our map. 



We thus proceed to investigate by degrees the valleys of the 

 one side of a longitudinal valley throughout its whole extent, 

 and then direct our attention to those of the opposite side. 

 Should there be several longitudinal valleys on the same de- 

 clivity of a mountain-range, which cross this declivity either 

 in contrary or in more or less parallel directions, we proceed 

 with these in the same manner, and examine those valleys 

 which are transverse at their origin or near it, but which, in 

 their progress, become longitudinal ones, and either remain so 

 to their termination, or when near it, again become transverse 

 ones. After completing fully the investigation of the one de- 

 clivity of the moimtainous district, we proceed to the other, in 

 order to treat it in a similar manner ; and we have thus our 

 attention more especially directed to the diflFerences which 

 exist on these two declivities, and which, notwithstanding their 

 pi'oximity, are often much greater than might have been ex- 

 pected previous to the investigation. Rocky masses, which 

 on the one side appear in moderate extent, occur on the other 

 in much greater development ; those which present themselves 

 here over an extensive tract, and in great thickness, are found 

 there in smaller quantity, or disappear altogether. Even the 

 external form of the two declivities, and the constitution of 

 the valleys, is not every where the same ; and hence it follows 

 that we cannot, from our knowledge of the one, draw our in- 

 ferences respecting the other, and that both must be investi- 

 gated with the requisite degree of care. 



When this examination has been finished, the next step in 

 importance is to combine the observations on the map, and 

 especially those relating to the extent and boundaries of the 



