304 QUIGKSILVEU DEPOSITS OF THE PACIFIC SLOPE. 



They niay be identical; but, if not, they are probably parallel, associated 

 fissures. Tlie developments accessible to me were insufficient to determine 

 this point.' 



With reference to the stockworks, my information is obtained at second 

 hand and is very imj^erfect. I hesitate, therefore, to express decided opinions 

 about them. It is noteworthy, however, that the most westerly of these 

 deposits, the Florencio Diaz, is approximately parallel to the Elvan Streak, 

 as is also the New Hope, to which further reference will be made below. 

 Most of the other stockworks have a strike nearly perpendicular to the 

 Elvan Streak. The clay wall makes an angle of about 45° with each of 

 these directions. 



The fissure system. — Tlic most momciitous quL'stioH concerning the structure 

 of this mine i.s the position of the principal fissures, those, namely, through 

 which the ore-bearing solutions found access to the productive ground; for 

 upon this question depends the plan to be adopted in developing the prop- 

 erty. The main fissures almost certainly coincide in direction with one or 

 other of the lines discussed above ; indeed, it may be assumed with some 

 confidence that either the clay wall or the Elvan Streak lies on the princi- 

 pal fissure or on one of a system of parallel fissures of nearly equal im- 

 portance. The existence of the stockworks is susceptible of explanation as 

 a subordinate structural phenomenon. The theory which was adopted in 

 developing the mine is that the clay is the hanging wall of the ore^earing 

 ground. The P^lvan Streak then represents a cross-course and the New 

 Hope is an isolated deposit in the hang-ing wall. Great weight is fo be 

 given to this opinion, which was formed by the daily study of the exposures. 

 It is evidently possible, however, that the main fissures may coincide in 

 direction with the Elvan Streak txnd the New Hope and that the clay wall 

 may represent a cross-course or a fault. I confess myself strongly inclined 

 to this latter view. 



Had the fault fissure been the channel of the ore solutions, one would 

 expect to find the chief ore bodies in contiguity to it and coinciding with 

 it in general direction. It is a common thing to find deposits of very 



' Early iu 1887 oro w,a.s struck iu tlie Bell tunnel workings which resembled that of the Elvau 

 Streak. This tenda to confirm the .above hypothesis. 



