REPORT ON MINERAL VEINS. 11 



It is admitted as interesting to remark, that in the midst of 

 the signs of disturbance which prevail in the bowels of the 

 earth, there reigns a certain symmetry and order, which indi- 

 cates a force of incredible magnitude, but slow and gradual in 

 its eftects. 



Further, that as a long period was required for the elevation 

 of the strata, the rents made in them are not all of the same 

 date, nor the veins all of the same formation. A vein that forces 

 the other out of its place, and preserves its own direction, is 

 evidently the more recent of the two. 



The parallel coats lining the walls or sides of the vein, which 

 are attributed by Werner and others to aqueous deposition, are 

 ascribed to successive injections of melted matter. 



Veins have been considered as traversing only the stratified 

 parts of the globe. They do, however, occasionally intersect 

 the unstratified parts, particularly the granite ; the same vein 

 often continuing its course across rocks of both kinds without 

 suffering material change. 



It is asserted that all the countries most remarkable for their 

 mines are primary, and that Derbyshire is the most considera- 

 ble exception to this rule that is known. 



This preference which the metals appear to give to the pri- 

 mary strata, is considered as consistent with Dr. Hutton's 

 theory ; and particularly as these strata, being the lowest, have 

 also the most direct communication with those regions from 

 which the mineral veins derive all their riches. 



In arguing further upon this theory, it is assumed that no- 

 thing of the substances which fill the veins is to be found any- 

 where at the surface ; and that, contrary to the allegation of 

 some that mineral veins are less rich as they go further down, 

 it is stated that this is not generally so, and that the mines in 

 Derbyshire and Cornwall are richest in depth, as they would 

 be if filled with melted matter from below. 



Again, it is said that if veins were filled from above, and by 

 water, the materials ought to be disposed in horizontal layers 

 across the vein; and that this opinion is sufficiently refuted by 

 the fact that rarely any metallic ore is found out of the vein, or 

 in the rock on either side of it, and least of all where the vein 

 is richest. 



The foregoing seem to be the most important allegations in 

 support of the Huttonian theory ; and I have taken them nearly 

 in the order in which they are given in Professor Playfair's il- 

 lustrations of this celebrated system. 



There is yet another doctrine regarding the formation of 

 veins, which, though it is not of modern date, and has had but 



