36 M. Mohs 1 Summary of Geognostical Phenomena. 



much which may serve as a good introduction to the search for 

 individual repositories, but are not of a nature to be intro- 

 duced in this place. 



Veins. — A great part of what has been said on beds is equally 

 applicable to veins. The most marked difference which can here 

 be taken into consideration between these two kinds of reposi- 

 tories of useful minerals, consists, as has been often stated, in 

 the phenomena of their positions. The beds of a bed-district are 

 (keeping peculiar circumstances out of view) parallel to one 

 another, and lie, without exception, conformably to the struc- 

 ture of the mountain-masses, for they are just on that account 

 beds, because this parallelism and this position, in reference to 

 the structure of the rock and the mountain-masses, are pre- 

 dominant in them. The directions of the strike and dip of 

 the veins of a vein-district may cut one another under all pos- 

 sible angles, and are in no respect connected with the struc- 

 ture of the rock or of the mountain-masses. They may even 

 be continued from one mountain-mass to another, for these re- 

 positories are just on that account veins, because they are in- 

 dependent, in regard to their position, of the mountain-masses, 

 and of their structure. It is assumed regarding veins of one 

 and the same formation, which, when several are present in 

 one district, form a magazine of veins (Gangniederlage), that 

 they possess at least a like strike, although their dip may be 

 different in amount or even in direction. The veins are gene- 

 rally more complicated in their composition than most beds are 

 (for there are also beds which contain the varieties of a large 

 number of species of different minerals, and thus surpass many 

 veins, even such as do not contain merely iron-ores, &c), and 

 the distinguishing several formations is thereby rendered the 

 more effectual, the more the knowledge of them is extended. 

 Experience has shewn that in an extensive district, in which a 

 large number of ma-formations had formerly been distin- 

 guished, these have been proved by further observations to be 

 so united with one another, or are connected and pass into one 

 another in such a manner, that it is no longer possible to as- 

 sign them boundaries with any precision ;* and, although this 



* Vide Kiilm's " GkogTtosie." 



