354 
GRANITE VEINS. 
[Ch. XXV. 
themselves into granite, in a manner analogous to that of the 
volcanic dikes of Etna and Vesuvius, where they cut and shift 
each other, or pass through alternating beds cf lava and tuff. 
No. 85. 
Granite veins traversing stratified rocJis. 
The annexed diagram will explain to the reader the manner 
in which these granite veins often branch off from the principal 
mass. Those on the right-hand side, and in the middle, are 
taken from Dr. Macculloch's representation of veins passing 
through the gneiss at Cape Wrath, in Scotland*. The veins 
on the left are described, by Captain Basil Hall, as traversing 
the argillaceous schist of the Table-Mountain at the Cape of 
Good Hope -J". 
No. 86. 
Granite veins traversing gneiss at Cape Wrath, in Scotland. 
We subjoin another sketch from Dr. Macculloch's interesting 
* Western Islands, plate 31. 
t Account of the structure of the Table-Mountain, &c, Trans. Roy. Soc. Edin., 
Vol. vii. 
