Ch. VII.] 



GRANITIC AND SCHISTOSE ROCKS. 



127 



though not so distinctly displayed. At Mousehole, the slate 

 thus situated only occurs in thin portions, apparently the 

 residue of the under surface of a mass of slate which once 

 existed : the slate, here, for the most part meets the granite 

 endwise, and is exposed in a horizontal section; so that, 

 following the beds of granite along their course, we enter on 

 the beds of slate, which appear to be a continuation of each 

 other, thus : 



Fig. 7. 



Junction of Granite and Slate at Mousehole. 

 V (Ground Plan.) 



Along the line of junction, which is much undulated, slate 

 sometimes constitutes a portion of a granitic block or concre- 

 tion ; and at others, the reverse holds good : that is, the line 

 of structure is often coincident with the line of junction, but 

 is sometimes indifferent thereto, separating a portion of slate 

 or granite as the case may be ; and, when this happens, the 

 one rock cannot be detached from the other ; as they form a 

 compact and individual concretion. At Mousehole, the nature 

 of the union in perpendicular sections may be detected on 

 a small scale, at many points, owing to the rocks having 

 been irregularly abraded by the waves. 



On the eastern side of Rosemodris Point, the slate is not 

 only seen reposing on the granite, at a considerable angle in 

 the upper part of the cliff', but the beds of both rocks meet 



