WANDERING BOY FAULTS. 163 



allel faults), the movement was undoubtedly similar to that of the minor faults, and 

 would bring the two portions of a faulted vein into somewhat the position that the 

 Wandering Boy and the Fraction veins, taken as a whole, occupy to each other. This 

 leads to the suspicion that the two occurrences were originally the same vein and 

 were separated by the Fraction fault. The veins in the two mines are similar in 

 strike, dip, size, and general characteristics. A fragment of the Fraction vein lying 

 farthest south on the 237-foot level and probably in a zone east of any exploration 

 on the 300-foot level has been plotted on the map. There is also shown its approx- 

 imate position on the 300-foot level, if it continues downward that far with the 

 observed dip. This fragment lies midway between the main portions developed in 

 the two mines, supporting the theory of the original identity of the veins. 



FAULTS NOT CORRESPONDING TO THE MAIN SYSTEMS. 



The northwesterly faults of the Wandering Boy 300-foot level are not so 

 closely related to the Wandering Boy fault as the northeasterly faults are to the 

 Fraction fault. Their trend is various, sometimes coinciding with that of the main 

 Wandering Boy fault, sometimes not. Their dip, as shown in fig. 48, is usually 

 steeply northeast, or in the opposite direction from that of the main fault, so that 

 while, like the main fault, they are normal, the downthrow is on the northeast 

 instead of on the southwest in accordance with the larger movement. Many of 

 them are, therefore, perhaps to be accurately regarded as independent minor faults., 

 resulting from the combined stresses of the major displacements. 



RELATIVE AGE OF FRACTION AND WANDERING BOY FAULTS. 



The Fraction fault movement partakes essentially of the nature of thrust 

 faulting, and, as has been explained, seems to be due to the horizontal shove exerted 

 by the intrusion of the Brougher Mountain volcanic neck. The Wandering Boy 

 fault, on the other hand, is a normal fault, such as is ordinarily due to gravity; and 

 the fact that faulted blocks are downthrown on the south, in the direction of the 

 dacite volcanic centers, leads to the belief that the downthrow was a part of the 

 general downfaulting in the neighborhood of these volcanoes, which, as described 

 on page 47, probably took place subsequent to the last important outbursts as a 

 result of collapse due to the expulsion of a large bulk of material from the under- 

 lying region. According to this the Wandering Boy fault is slightly but distinctly 

 subsequent to the Fraction fault. 



ORE IN WANDERING BOY VEINS. 



Like most of the Fraction vein material, and much of the material in the Valley 

 View, most of the quartz in the Wandering Boy thus far developed is low grade, or 

 even practically barren. Good assays are obtainable, but even limited masses of 



