284 Dr. Mac CiiUoch on the Junction 



gating, with an unbiassed mind^ all the most minute circum- 

 stances, whether direct or analogical, which may tend either 

 to reduce them under the laws already admitted, or to the 

 establishment of a new ride. 



It only remains, in concluding this subject, to inquire how 

 far the facts above detailed are irreconcileable to the theory 

 which supposes granite to be of igneous origin. 



As far as the apparent geological and mineralogical transi- 

 tions between the two rocks are concerned, if the explanation 

 above given is satisfactory, they in no way interfere with it. 

 According to that view, the same, or analogous phenomena, 

 might result, had the sandstone been deposited on gneiss ; 

 the formation of the granite and that of the sandstone are as 

 independent in point of cause and time, as if they had been 

 separated by intermediate rocks of any extent. The only dif- 

 ficulty, then, that remains, as far as the igneous origin of the 

 granite is concerned, relates to the very oblique or inclined 

 position of the sandstone above it. Now, in the views of those 

 who maintain that granite is not of igneous origin, and who, 

 in general, equally maintain that the superincumbent strata 

 have not been elevated, since they cannot have been elevated 

 by that rock, this question needs no examination. The sand- 

 stone is in its natural position. Whether the granite, in this case, 

 has been elevated so as to elevate the sandstone with it, or 

 whether that has been deposited in its present position, it offers 

 no further difficulty, than that which is of daily occurrence, in 

 examining the primary strata. Quartz rock, stratified with 

 similar regularity, is often equally, or still more highly 

 elevated ; and the same regularity is often found in other cases 

 of highly inclined strata, whether granite is present or not ; 

 leaving no doubt, that if it is impossible that strata should be 

 deposited from water in positions highly inclined, they may at 

 least be elevated to high angles, by posterior causes, without 

 losing their evenness or continuity. 



It is to be concluded, that the granite is in this place prior 

 to the sandstone, because no veins are found passing from it 

 unto the latter, and because, as yet, no instance of granite, 

 subjacent to secondary strata, has been found to send veins 

 into them. 



