8 ATTENTIONS FROM COMMANDING. OFFICERS AT TUCZON.—DOS CABEZAS. 
analogous to a meteoric mineral that I described as forming the chief part of the Bishopsville 
(S. C.) meteoric stone. It is this feature that makes your iron entirely peculiar. To see this 
trait, you have only to polish a little surface, and etch with hydrochloric acid, when the surface 
becomes speckled over with the white earthy mineral, imparting to it a porphyritic character ; 
but to see this well, will require the aid of a microscope. 
“Large quantities of the white mineral remain undissolved after the solution of the main 
mass in the acid; and floating among the residuum may be seen also a dark gray flocculent 
matter, which I took to be the meteoric mineral I have named Dyslytite. Much of the white 
earthy mineral is thus seen to be in grains, perfectly rounded; some of which are transparent 
and resemble hyalite; other portions of them are milk-white and nearly opaque. These last 
are soft, and precisely resemble chladnite.’’ 
February 22.—Again got under way, starting about noon; but, instead of taking the emi- 
grant route via the mission of San Javier del Bac to the Cienega de los Pimas, thereby making 
a great détour, travelling first south, and then due east, we took a course direct for the gap, 
there intervening apparently a smooth and uniformly ascending plain; camped without water, 
but an abundance of grass. The officers of the garrison, and Inspector General Gomez, ac- 
companied us to the camp; thus adding another to the list of polite attentions and serviceable 
offices rendered us by these gentlemen, for which we are under many obligations.  . 
February 23.—Soon after leaving camp this morning, we were compelled to diverge from our 
course, owing to the thick growth of cactus, and were finally compelled to cut a road through it. 
Reaching the emigrant road, we turned almost due east, and travelled over an undulating 
country, the swells increasing as we neared the entrance of the gap, where we encountered a 
cañon debouching from this pass and opening out into a broad drain or valley to the northwest. 
Entering this cañon we commenced its ascent, travelling through deep and heavy sand, alter- 
nating with contracted meadow patches, hemmed in by walls, approaching verticality, of 
irregular, shapeless masses of rock, generally of a metamorphic character; limestone, granite, 
copper-green, and a pudding-stone, all being found without any marked characteristics or 
apparent order of superposition. Camped at the first water, with grass and wood, having made 
18.4 miles. 
February 24.—Made an examination of the country adjacent to the camp, and found that 
this cañon is the main drain of the gap or depression, and that the slopes on either.side are 
rough and broken up by deep ravines and washes. Our teams started at nine and a half, and 
were soon forced to the hills by the narrowing of the cañon, rendering it impassable for wagons 
without much labor bestowed on removing the obstacles. Avoiding this cañon by a rough and 
rugged road, we again entered the valley, and thus continued through long, smooth meadows, 
and over rough and steep pitches (fortunately not high) for nine miles, when we ascended the 
table-land on our left and commenced the approach to the divide, following a set of wagon-trails. 
On the table-land had a good road over a red gravelly soil of decomposed igneous rock, yielding 
a rich growth of grama grass, which, although not in season, is nevertheless very nutritious, 
being perfectly cured hay, standing as it grew.- Camped near the divide between the waters of 
the Tuczon and those of the San Pedro, without water and but little wood, having made 13.5 
miles. 
February 25.—Last night was cold and squally, a rain setting in immediately after dark. 
Started early and soon made the summit of the divide, whence we had a view of the San Pedro 
valley—a dry, parched-looking plain, bounded on the east by a low, bare ridge, beyond which 
loomed up in the blue distance the Dos Cabezas, the most striking and prominent landmark in 
this region. The trail bearing too much to the south, we left it, and turning eastward de- 
scended to the San Pedro, where we camped. From the summit there is a gradual slope to the 
valley proper, or bottom, which we entered by an abrupt descent of about sixty feet. This 
bottom is bounded on both sides by an irregular zigzag step, much indented by deep washes, 
and is at this point about three miles wide. It is covered with a growth of grass, now dry and 
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