STEUCTUEE OP CHIEICAHUI EANGE—PUEETO. 
149 
The order of the strata on the western slope of the Chiricahui, along the trail, was— 
Granite, felspathic. 
Serpentine, auriferous. 
Hornblendic black slate. 
Quartz, ferruginous and drusic. 
Jaspery conglomerate, (exposed,) 90 feet. 
Sandstone, with cleavage lines, 60 feet. 
Limestone, compact and metamorphosed, 100 feet. 
As has been stated already, it is difficult to give the estimate of the jasper conglomerate with 
any approximation to truth, as it is not fully exposed. The serpentine is in thin beds, and the 
black slate is not more than fifty feet thick. The ferruginous quartz is rather an altered or 
metamorphic sandstone ; an interval of 500 feet at least here separates the limestone from the 
primary rock, and it is probable that, though not observed at the mouth of the San Francisco 
river, this intervention exists there also. 
It may be remarked of the limestone strata which were encountered on the slope of the 
Calitro range dipping eastward, that they showed themselves there for the first time, that rock 
not having been observed on the eastern slope of the Sierra Nevada, nor at any of the small 
ranges on the desert or up the Gila. At Goat hills, and a few other points, the conglomerate is 
the only rock exposed which should not be confounded with the sandstones and conglomerates 
below the limestone ; lithologically dissimilar, they are also of very different ages. 
“ PUERTO DEL DADO.” 
The pass through the Chiricahui, so called, is a narrow, winding trail; it opens up into 
small valleys of unusual fertility, enclosed by mountain walls. There are no secondary rocks 
in the Puerto. The whole mountain is a mass of primary rock, of which a reddish felspar 
granite, mostly of a coarse character, forms the chief part; veins and dykes of porphyry felspar 
cut through this and reach the summit, and, from its being of a finer texture and less acted on 
by the weather, form those turretted summits which, visible from a great distance, and situated 
upon the apex of the hill, constitute what are called the Dos Cabezos. These cabezos are 
repeated in several places along the crest wherever the porphyry dyke happens to be produced, 
but those which are known as such are on the most prominent point of the mountain. At the 
western entrance of the canon several quartz veins running north and south cross the trail, one 
of these being 40 feet in width ; accompanying these is a blue quartzose chalcedonic rock. In 
the granitic rock the felspar crystals are large, distinct, and reddish, and everywhere through 
these smaller, as well as the larger hills, felspar dykes, rising at an angle of 60° from the east, 
cut their way and form the angular crests. 
The whole mass of the mountain is more felspathic than granitic—thus, felspathic rock; rock 
felspar crystals, in a felspar paste ; felspar rock amorphous ; felspar rock, with rhomboidal 
cleavage; porphyritic felspar, i. e., quartz and felspar—a rare rock ; quartz veins, both ferru¬ 
ginous and vitreous, which usually run at a right angle to the felspar dyke, whose general 
direction is N. 60° E. Such is the constitution of the whole mass of the Chiricahui, from the 
entrance to the exit of the canon, a breadth of nearly ten miles. 
Dykes of augite, in some places 15 feet in width, cut through the felspar rock in the creek bed 
on the east slope of the Puerto, and thin beds of serpentine are found occurring on this as well 
as on the western entrance of the Puerto. 
Although properly considered as one mountain mass, elevated synchronously, yet, in crossing 
