300 REV. J. F, BLAKE ON THE 
considerable quantity of dark-green rock, “diabase,” which has 
fissured and streaked the granite by its intrusions, and has torn 
off fragments of this rock, of felsite, and of conglomerate, in- 
Fig. 5.—Plan of Ogof-Llesugn. 
. 
\] 
> 
Ea) 
i 
/ 
ear Granite. Conglomerate. 
ae | Felsite. | Shales. 
Sandstones and slates. 
—— Diabase. 
discriminately, and borne them upwards. It is only, therefore, 
by chance that the granite and conglomerate ever come together, 
z. €. Where the diabase has not intruded between them. There may 
be a foot or two of such a conjunction on the sides of the fissure ; 
but the greater part of this is bounded by the “diabase.” The 
masses on the foreshore are absolutely not in contact with the granite 
at all, but surrounded by the “ diabase,” and altered by it to a 
much more solid rock. The granite and felsite are treated in the 
same way. It seems to me an interesting spot to compare the 
appearances of an intrusive and a faulted junction, since both are so 
plainly shown and so clearly contrasted, that the truly faulted 
nature of the junction between the granite and the Cambrian cannot 
