22 Faults. 
erning normal faults, must be reversed in this case. This 
class of faults are of very rare occurrence in this coun- 
try, while in the Witwatersrand district, in South Africa, 
they are not uncommon. In order to determine whether 
the fault met with is a reversed or a normal fault, the 
engineer can only determine this by making a careful 
study of the earth’s crust movements of the district in 
which the fault occurs. It will be observed that if the 
stratum in the figure were eroded off at O the outcrop 
of two veins would apparently be shown, when in fact 
only one does exist. 
Figure 11 
x is the plan 
ty of a faulted 
vein. On driv- 
ing the drift 
A B, a fault 
was met at A. 
The fault plane 
was found to 
4 
MMMM 
x 
dip 50 degrees 
in the direction 
FIG. 11. 
Plan of a Faulted Vein. . M L, and to 
rection AF. AB 
is the strike of the vein and it dips 75 degrees in the 
direction B K. It is required to find the continuation — 
or faulted portion of the vein, which is evidently some- 
where along the fault plane G F. 
Lay off the workings to scale in horizontal section. 
Assume any convenient vertical depth, say, 100 feet, 
then 100 + Tan. 75° equals the distance B D. At D 
draw the line D C, parallel to A B. In like manner 
100 + Tan. 50° equals the distance M N. At N draw the 
