THE AEIZONA MINES. 



69 



development of vegetation on this sierra ; tlie rougk surface of its sides is covered with a dense 

 growth of shruhbery, of which some are quite trees, and grass is luxuriant in all the valleys. 

 There are several species of oak, and on the summit is found a cedar; though this ridge does 

 not fully reach the pine region. This sierra partakes of all the physiographical features of 

 the Santa Barbara, Santa Cruz, and other links of the Sierra Madre further east. The Sierra 

 del Pajarito, with its dependencies already referred to^ constitute one and the same mountain 

 system, properly characterized by the word Cordillera, and, taken collectively, are known as the 

 Arizona Mountains. This word probably belongs to the soft Papago language, but we could 

 not learn its meaning. The Arizona Mountains are rich in silver, copper, and gold ; evidences 

 of numerous and well-worked mines are still to be met with. The eastern slope of the Sierra 

 del Pajarito (Los Nogales) is especially worthy of exploration with reference to a development of 

 its mineral production. Specimens of silver from this locality were analyzed, and the result 

 will be found in its proper place. 



The Sierra del Pajarito constitutes a part of the divide already referred to, and has been inten- 

 tionally dwelt upon at length for the purpose of referring the other sierras to it as a standard 

 of comparison in consequence of its typical character, both as to its hypsometrical and geologi- 

 cal features. 



Looking westward from the peak of the Sierra del Pajarito, a rugged net of mountain ranges 

 is spread out, made up of metamorphic rocks ; and though the single sierras do not rise very 

 high, they form a very bold mountain relief by the close, uninterrupted texture of the inclined 

 plane which constitutes them. (See outline sketches Nos. 34 and 35 of the azimuth line.) 



At a distance of about sixteen miles another cordillera is visible, between which and the 

 Sierra del Pajarito very little drift occurs ; and this is confined only to the intervening valleys, 

 where mesas and lomas, forty to fifty feet in height, are formed by the drainage from the sur- 

 rounding mountains. Near where the drainage from the east slope of the Sierra de la Escon- 

 dida joins that coming from the southwest side of the Sierra del Pajarito, a point just south of 



BECTION ON THE NOSTH SIDE OF THE CEBBO DB 80N0RA. 



the line, permanent water is to be found. It is under a cleft of igneous rocks, and does not pro- 

 perly deserve the name of a spring, but is rather a tinaja supplied by water trickling through 

 the rocks from water-holes above. From the character of this place is taken the name Escon- 

 dida, (agua escondida meaning hidden water,) a term which is generally applied to the whole 

 sierra. In its orographical character, this sierra is but a volcanic dyke, (a) towering up into an 

 isolated, rugged crest of igneous rocks, composed of amygdaloid, porphyritic, and trachytic com- 

 pounds, intersected and overlaid by contorted and overthrown crystalline strata of a coarsely- 

 grained and frequently disintegrating feldspathic syenite(c.) This syenite is sometimes meta- 



