100 ON THE CONVOLUTIONS OF STRATA, 



are here 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. The granite enters among the strata in several 

 large dikes or veins, which at first are a hundred yards in 

 widen ess, but which rapidly taper away to a small breadth. 



Along the whole line of junction, from this point north- 

 ward to the burgh of New Galloway, at a distance perhaps of 

 two miles, a scene of almost perpetual interest presents itself, 

 being a repeated display of the penetration of the stratified 

 mass by the granite ; and the rock being but thinly covered 

 with soil, these circumstances come frequently into view, and 

 particularly at the spots known by the name of Sight Knoll, 

 and the Hog Knoll. In 1788, I had seen an instance of a 

 dike penetrating the strata, and distinctly emanating from the 

 mass of granite, in such a manner as to convince me that it 

 constituted with that mass one uninterrupted and identical 

 substance. On my return in 1807, when the subject had ac- 

 quired a peculiar degree of interest, in consequence of the dis- 

 cussions carried on in this Society, the progress of vegetation 

 had been such as to conceal it entirely ; but being well con- 

 vinced of the reality of its existence, I determined to recover 

 it, and employed several workmen to clear away the earth and 

 vegetable matter from the most interesting spots. At various 

 distances, within fifteen or twenty yards from the main gra- 

 nitic mass, several masses of granite, or portions of veins, 

 made their appearance, which I conceived to be emanations 

 from the great mass, although their junction with it was con- 

 cealed. I was anxious to trace some of these to their source ; 

 and after the labour of several days, I at last succeeded with 



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