FISSURES OF THE NEW ALMADEN.. 323 



the altas of the two groups once more assume a position of approximate 

 parallelism, which shows that they remain distinct throughout. 



Another test of the distinctness of the fissures can be applied, and, 

 indeed, one which is of no small importance for the mine. The average 

 strike of the north group in its upper portion is on a line not far from S. 

 50° W. magnetic, and, as shown by the north and south section through 

 the shaft, if the north fissure were continuous it would reach the surface 

 about four hundred feet south of the Randol shaft. Having arrived at this 

 conclusion, I examined the surface, and did in fixct find a line of dolomitic, 

 botryoidal croppings north of the road leading from the office to the Randol 

 shaft above the Randol group of bonanzas, and which seemed to strike for 

 other croppings on which a little tunnel has been opened about four hun- 

 dred and fifty feet south magnetic from the shaft. These croppings thus 

 strike very nearly in the same direction as the altas of the Randol group 

 of ore bodies on the 1,050-foot level, and are very close to the position 

 indicated for a cropping of this fissure. In my opinion they represent 

 such a cropping and complete the proof that the New Almaden mine pos- 

 sesses two important fissures, along one of wdiich the south group of 

 bonanzas has been followed from the surface, while the north group lies 

 upon the other. One fissure underlies the great tongue of hanging coun- 

 try, the other intersects it. 



Ore in the inclosed wedge. — Betwceu the two prluclpal fissurcs a wedge of 

 country rock exists. It is not uncommon for great masses of this description 

 to be inclosed on both sides by ore-bearing fissures. Such was the case on 

 the Comstock and also in the Ruby Hill mines at Eureka, Nev. Ground 

 thus inclosed is seldom solid and subsidiary fissures leading into it are often 

 ore bearing. In the New Ahnaden mine the ore is not confined to well de- 

 fined fissures. It is true that ore can be followed from the top of Mine Hill 

 downward to a depth of ],G00 feet practically without a break; but the sec- 

 tions show that at many points the fissures are systems of associated open- 

 ings rather than simple ruptures. The north and south section through the 

 Randol shaft shows a section of the Velasco, Theatre, and several of the 

 Santa Rita bodies, which is especially illustrative of this structure. The 

 section shows that the wedge of ground between the principal fissures is 



