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has been contended, by some geologists^ that the veins 

 and slate are contemporaneous; others have, however, 

 come to a diiFerent conclusion. It has been argued, from 

 the fact of some of the granite veins traversing the con- 

 temporaneous quartz veins," and from the fragments of 

 slate which are frequently found in them 5 that the gra- 

 nite veins are of a more recent formation than the slate 

 which contains them. They also contend, from the gra- 

 nite of the veins being generally different in many re- 

 spects from that of the mass, from the fragments of slate 

 not being found in the mass as well as in the veins, and 

 from the slate being rarely overlaid by any part of the 

 granite mass," that the main body of the granite may 

 have preceded the slate, although the granite veins (as 

 veins) may have followed it. 



The apparent alternations of granite and slate, at dif- 

 ferent places, maybe caused either by the occurrence of 

 highly inclined granitic veins, or by the slate filling up 

 the irregularities in the granite. 



It would appear, from all that has been here observed, 

 that two primitive rocks, at or near the point of their 

 junction, sometimes alternate with each other, and ren- 

 der it probable that, although strictly speaking the main 

 body of the one may be said to be anterior to that of the 

 other, the formation of the former was scarcely finished 

 when that of the latter began. It may be difficult else 

 to account for the fact, that the granite and clay slate ex- 

 hibit a change in some of their qualities, almost wherever 

 a junction occurs. 



Veins of steatite are abundant in the serpentine for- 

 mations; they are from several inches to 3 feet wide, their 

 colour from white to yellow, green and purple. They 

 have distinct walls, and are as regular as true veins. 

 Fragments of serpentine and calcareous spar are some- 

 times found in them. They bear a closer resemblance 



