VEINS IN GRANITIC ROCK. 573 
a manner as to appear continuous with the separated parts of one of 
the veins. 
These faults, as exhibited in the sections, sometimes affect one of 
two contiguous veins, without affecting the other; or they affect the 
two differently. In figures 10 and 11, the two veins are but a few feet 
apart: yet in one, there are four faults, and in the other five ; more- 
over, in the latter, one of the principal faults has a direction contrary 
to any in the former. Figure 15 is another example of the same fact: 
the vein A is about six feet above the vein B; and although so near 
one another, there is an additional fault in the upper vein. The lower 
vein is also remarkable for its oblique direction (7 7) between the first 
two faults. 
Besides the faults described, there are also interruptions in veins, 
where the parts of a vein are distant though parallel. Figure 16 
represents one of the very many instances 
of this species of fault. The parts were ee 
never united, being separated by the inter- — 
vening granite or gneiss. ‘This example = 
lies a few feet above figure 13, in which are | 
faults of the ordinary kind. In figure 3, 
both faults and interruptions of the kind here described occur in the 
same vein. 
Origin of the Granitic and Epidotic Veins. 
The two theories for granitic veins find many arguments for their 
support in the facts which have just been considered. 
In favour of the theory of segregation, we observe—(a) that the 
riband vein in figure 9, exemplifies a veined structure produced 
where there could not have been a separate injection of the seve- 
144 
