158 



GEOLOGY OF TONOPAH MINING DISTRICT, NEVADA. 



of these two intersecting directions of faulting has been a third diagonal system, 

 which represents the direction of equal faulting. 



On a plane projection, with closer spacing of faults, or a greater number of 

 thorn shown on a smaller scale, the situation is again shown in fig. 50. It may 

 be remarked that to obtain such a resultant there need not necessarily be any 



N 



Downthrow 



W 



O 

 o 



IE 



FIG. 50. Diagram showing horizontal plan of equal and equally spaced faults belonging to two systems intersecting at 

 right angles, the north-south system having a regular downthrow on the east, and the east-west system a regular 

 downthrow on the south side. The heavy zigzag line represents one of the lines of equal faulting, the shaded squares 

 one of the zones or blocks of equal displacement. 



correspondence between the direction of displacement (whether up or down) of 

 the two systems. If we reverse the movement of either of the fault systems, 

 for example, if in the figure (to be understood with the aid of the stereogram) 

 the north-south faults are downthrown to the west instead of to the east, a 



