Ch. VII.] GRANITIC AND SCHISTOSE ROCKS. 125 



the ends of which, however, do not abut against the granite 

 in an abrupt manner, but repose on it in such a manner as 

 to fill all the inequalities of the irregular curvatures of the 

 fundamental rock : so that, at the surface of these rocks, the 

 seams of structure developed by partial disintegration, not 

 only run in the same direction, but traverse both rocks in 

 continuous lines parallel with the bearings or strike of the 

 strata. 



The granite of Galloway, according to Sir James Hall, 

 presents similar indications, at its junction with the slate. 

 " In the bed of the river, at the High Bridge of Dee, the 

 granite dips from the centre of the mass at an angle of 45, 

 and the strata lie upon it in a conformable position : but, at 

 the southern extremity of the Hill of Lauren, at Loch Ken, 

 the character of the junction is very different; the strata 

 here are nearly vertical, stretching from north to south. The 

 line of junction which occurs on the face of the hill towards 

 its summit, cuts the strata at various angles, sometimes nearly 

 at right angles ; and the strata thus abutting endwise against 

 the granite, the two substances are, as it were, spliced into 

 each other."* 



Other examples might be quoted on this subject, but the 

 fact that the granite and slate meet under such different 

 aspects, is well established : and, indeed, it follows, from the 

 curved outline and projecting masses of the former rock, 

 which run into the slate after the same manner, as the land 

 into the sea, that the strata having a regular strike or bearing 

 must sometimes abut against the granite. But, notwithstand- 

 ing this apparent irregularity of position in these rocks at 

 their junction, there is in reality no want of order ; a careful 

 and minute inspection will remove the appearance of con- 

 fusion which seems, on a cursory view, to prevail ; and the 

 clue by which this labyrinth may be unravelled, is the struc- 

 ture of these rocks, or that arrangement by which their con- 



* Royal Transactions of Edinburgh, vol. vii. p. 99. 



