WOODMAN: GOLD-BEADING SLATES OF NOVA SCOTIA. 395 
of the beds which are exposed to-day. This is shown, not only by 
the amount which can be demonstrated to have been eroded even 
before lower Carboniferous times, but also by the almost entire 
absence of faults at the first period of folding. 
Formation of bedded veins, by solfataric action from below. 
The main portion of the process t,ook place rapidly, but some 
veining lingered until after part of the later jointing, or else at 
intervals new activities arose, in no case with the same power as 
the first. A small amount of gold may have been brought up in 
the solutions. The presence of the veins prevailingly in stratifica¬ 
tion planes is another point concerning the great pressure under 
which the series lay, and the cross-stringers show that the rocks had 
already begun to suffer differential stresses sufficient to cause irreg¬ 
ular fractures. Of the primary planes of weakness, those were most 
pronounced which lay at the contact of two beds of diverse physi¬ 
cal characteristics, and the solutions chose these in many cases. 
Metamorphism and concentration of much of the ore. The 
possibilities in regard to the origin of the pyrite and arsenopyrite 
may be grouped as follows. (1) The sulphides in both country- 
rock and veins may have a common or separate origin. (2) Those 
in the sediments may be the product of metamorphism of original 
ingredients, or may be due to solfataric action; and those in the 
veins may be concentrations from the sediments, or have resulted 
from the same process which filled the veins. Neither can be 
proved with the knowledge we possess at present. Both slate and 
whin are thickly impregnated with the sulphides, and as much 
away from the veins as near them; and often in positions where 
solfataric solutions must have penetrated very thoroughly and have 
gone far from their place of entrance. Besides, they are ordinary 
products of metamorphism, where the proper ingredients are 
present in the rocks. If their source were deep-seated, however, 
their relation to the veins remains to be determined. At present 
it is not possible to decide this with accuracy. It appears that 
much of the sulphides in the veins has been concentrated from the 
country-rock, like the gold. 
Whatever the facts concerning the origin of the ingredients of 
the sulphides, their concentration is easier to follow. It occurred 
mainly before the first period of folding and, of course, after the 
entrance of the veins. The presence of the ores along bedding- 
planes, and their folding with the sediments, indicate this. This is 
