106 DISPOSITIONS, FRACTURES AND 



and nature of which the most accurate correspondence 

 can still be traced, are proofs of motion that cannot 

 be mistaken. It would be intruding upon the reader's 

 patience to dwell on the further important proofs that 

 are seen, in the great change of inclination between 

 the separated parts, which sometimes occurs in these 

 cases. But it is essential to notice the effects often 

 produced at the places of fracture ; which consist in 

 the comminution and separation of those fragments 

 that have afterwards constituted the veins, or which, 

 at least, enter into their composition. Thus, the 

 conglomerate veins noticed in a former chapter, are 

 evidences of the force which has attended the separa- 

 tion of the strata, from the fragments of which they 

 are chiefly formed. 



Of the Causes of the Displacements of Strata. 



Having already adduced all the arguments neces- 

 sary for proving that the elevated strata have under- 

 gone changes of position, it is proper to examine those 

 cases where, not only the fact of displacement is seen, 

 but where its immediate causes, or perhaps more 

 strictly, concomitants, are present. These are to be 

 found in the appearances which take place at the 

 junction of Granite and the Trap rocks with the strata, 

 the minuter circumstances of which are particularly 

 described in their more proper places, (chapters xxiv. 

 and xxxix.) In these, we can trace examples, not 

 only of every modification of elevation, fracture, and 

 slide which has been described, but the phenomena of 

 curvature also that are considered in the succeeding 

 chapter. The more immediate causes of the disloca- 

 tions are here obvious ; as they consist in the intrusion 

 of masses of matter, which every accompanying cir- 



