Vol. 4] 



Eeid. — The Comstock Lode. 



185 



secondary fissures at greater depths. The "west vein" and the 

 "east vein" at the surface have been carefully described many 

 times by previous observers,* and the fact that only the "east 

 vein" carried values has caused much discussion. This "east 

 vein" is merely the gash which reached the surface, thereby ap- 



FiG. 2. — Ground plan of Comstock lode, showing disposition of faults. 



pearing as a vein occupying a fault plane and resultant fissure. 

 These three gashes — the surface "east vein," the famous bo- 

 nanza, and the "vein" now being worked, all have an identical 

 origin. Their formation lies in the fact that the lower part of the 

 hanging wall block has settled more than the upper, relative to 

 the foot wall, and has been torn apart by the stresses developed. 

 This form of ore deposit is rather new, and because of its evident 

 importance deserves a distinctive recognition. The term "gash 

 vein" is not suitable, obviously, and the name "rift vein" is sug- 

 gested to cover the structure. 



Gold Hill. — The bonanzas of Gold Hill are found in the lode 

 proper, near the east wall, and east of the low grade quartz. The 



* G. F. Becker, op. cit. Clarence King, ' ' Survey of Fortieth Parallel, ' ' 

 Vol. III. John A. Church, "The Comstock Lode — Its Formation and 

 History. ' ' 



