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ILLUSTRATIONS OF THE 



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■*Fr 



Note xi. § 42. 



Fra£lure and dijlocation of thejlrata 



'i 



^ 181. The greateft part of the fads relative to 

 the fradture and diflocation of the ftrata, belongs 

 to the hiftory of veins. The inftances oi Jlips^ 

 where no new mineral fubftance is introduced 

 between the feparated rocks, are what properly 

 belong to this place. The frequency of thefe 

 and their great extent, are well known where- 

 ever mines have been wrought. In fome of 

 them no opening is left, but the flipped ftrata 

 remain contiguous ; in other cafes, there is in- 

 troduced an unconfolidated earth, often a claj, 

 which may be fuppofed to have come from 

 above, and very probably to have been car- 

 ried down by the water. In fome fuch cafes, 



r 



however, there are not wanting appearances, 

 which fhow the matter in the flip to have been 

 forced up from below, as we find it to contain 

 fubftances which could not have come from the 

 furface *. 



182. A 



/ 



*. Unconfolidated earth contained between the iides of 

 a rock that has flippedj is freq^uent in Cornwall, and is 

 called a Fleukan* 



