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outskirts of the desert, in a country clothed with only bushy mes- 

 quite and cacti, and almost destitute of water, there exists a region 

 which, from the character of its veins, appears to contain greater 

 mineral wealth than any other part of Arizona yet explored. It is 

 situated in the center of a large plain, forming part of the Papa- 

 goria, and about eighty miles by trail northwest of Tubac. 



The veins which I observed occur in a quartziferous porphyry 

 and in an amygdaloid rock. This latter has a brown compact base, 

 containing numerous acicular crystals of triclinic felspar, and cal- 

 careous spar in impregnations and small threads. Cavities, some 

 filled with quartz and others with Delessite, are frequent. In this 

 formation is the Cahuabi vein. It is from twelve to fifteen inches 

 thick, and consists of quartz and heavy spar, containing argentifer- 

 ous copper-glance, galena and black tetrahedrite. The ore of this 

 vein is said to average from one hundred and fifty to two hundred 

 dollars per ton. 



The Tajo vein, about three miles from the Cahuabi, occurs in 

 the same rock and is about two feet in thickness. The gangue is 

 barytes and quartz. The ore consists of copper-glance, galena and 

 tetrahedrite with some blende. With the copper-glance is associated 

 copper pyrites. This vein contains also considerable metallic gold. 

 The ore is said to vary from one hundred and fifty to one hundred 

 and seventy dollars per ton. 



Four miles west of the Tajo is a vein which traverses a quartz- 

 iferous porphyry of the same character as that which bears the 

 gold-quartz veins of Arivaca. The gangue is quartz, and contains 

 black tetrahedrite and some vitreous copper. 



A great number of veins of quartz and barytes occur in these 

 two formations, the latter seeming to prefer the amygdaloid rock. 

 One vein of barytes, containing a " bonanza " of sulphuret of silver, 

 was found and worked by the Mexicans, and several specimens of 

 heavy spar associated Avith silver-glance from various localities were 

 shown me. 



The San Pedro Mines. — These are about thirty-five miles cast 

 of Fort Buchanan, and were opened by a St. Louis Company. The 

 ores that I have seen from this locality are tetrahedrite and massive 

 copper-glance, containing copper pyrites, with quartz and barytes 

 for gangue from the San Pedro vein, and galena with iron pyrites 

 from the St. Paul mine. 



These veins were being opened and promising well, when the 

 Company abandoned them on the account of the assassination of 

 the employf^s by the Peons. 



The San Pedro river near these mines is said to be capable of 

 furnishing sufficient water power for extensive reduction works. 



