[ 17 ] 



III. Some Remarks on Mineral Veins,S,-c. By R.W. Fox, Esq.* 



TT appears to be a question wortliy of investigation, how far 

 * the internal structure and temperature of the earth may be 

 connected with electricity and magnetism, and with the mete- 

 orological phaenomena observable at its surface. 



Both the Wernerian and Huttonian hypotheses seem to 

 have a tendency to involve the subject of geology in obscurity, 

 rather than the reverse ; especially when applied to the expla- 

 nation of the origin of veins. 



How, for instance, could very oblique open fissures in the 

 earth, sometimes many yards wide, and of great but unknown 

 length and width, exist for a moment without being closed by 

 the weight of the superincumbent mass? Besides, I apprehend 

 that in Cornwall, at least, the width of the veins, taken in the 

 aggregate, is not found to diminish in depth ; although some 

 of our mines have been worked to the extent of from 230 to 

 240 fathoms under the surface. 



Veins are, however, often found irregular in their thickness 

 at different depths; and when this circumstance and their 

 frequently great incUnation from the perpendicular are consi- 

 dered, it may be asked, why, if they were originally rents in 

 the rock, they do not abound with fragments of it ? 



Proximate veins often unite for a certain distance, either 

 horizontally, or in their descent, and appear to have the cha- 

 racters assigned to contemporaneous veins. If so, it is im- 

 possible to imagine them to have been open fissures, as the 

 included rock would have had no support. If we suppose 

 them to have been formed from fissures produced at different 

 periods, it may be questioned, why the old rents, where the ad- 

 hesion might be presumed to be the weakest, did not re-open ? 

 whereas neighbouring veins are sometimes not quite parallel, 

 but often far otherwise in descending into tlie earth ; and the 

 direction seems to be wholly independent of the cleavage or 

 dip of the containing rocks ; and in iiict they pass through 

 different rocks, such as granite and clay-slate, without suffer- 

 ing any alteration in their course at the place of junction. 



But if it should be admitted, for the sake of the argument, 

 that such open fissures as have been alluded to, could exist, 

 and that the substances found in veins could all be held in so- 

 lution, and mii^lit be deposited in the actual f()rms and com- 

 binations in which they are now found, — there is nothing like 

 horizontal stratification to be seen even in the largest veins; and 



• (.'oinniiiiiicatcd by tlic Author. 

 .V. 6'. Vol. 6. No. 3J. Juhj 182y. D the 



