On Mineral Veins. 229 
One object of this paper is to show that, both as regards 
the formation of the veins and their relative age, these con- 
clusions have been too hastily drawn. 
As regards the relative age of veins it has been held 
that of two veins crossing each 
other, where one is unbroken 
(a Fig. 1) and the other faulted 
(6 Fig. 1), the unbroken vein indi- 
cates the latest fracture, and that 
the faulted vein has heen dislocated 
by the sliding of the sides of that 
fracture. But this evidence of the 
relative age is not conclusive, be- 
cause the faulting of the vein b 
may not arise from the sliding of 
the sides of the fissure a, but from 
a being the oldest vein, and there- 
fore interrupting the action of the 
a 
alse 
pb 
aL 
Fia. 1. 
force which has formed the vein 6, thus causing an apparent 
dislocation, when the deduction as to age will have to be 
reversed, and a@ must be considered ag the oldest, not the 
latest fracture. 
Cases are frequently met with where several parallel 
veins are faulted in crossing a con- 
tinuous or unbroken vein; and ° 
the respective distances of the 
parallel veins from each other 
should correspond on each side 
of the unbroken vein if the 
faulting of these veins was owing 
to a dislocation caused by the 
sliding of the sides of the un- 
broken vein. But instances are 
common where this could not be 
the case. For example, Fig. 2 is 
a plan or horizontal section of the 
intersection of several mineral 
veins (0, c, d, e, f), with an un- 
broken vein @, where each of 
these mineral veins reforms at 
different distances from the origi- 
Fia. 2, 
nal line of bearing ; and it would be impossible to account 
for the faulting by the sliding of the sides of the cross vein a. 
Fig. 2, Hanson Mear mine. 
