74 NEW TRACKS IN NORTH AMERICA. 
sible to our instruments: found it to be 825 feet high, and | 
this was below the average of the walls; so it is easy to 7 
conceive the relative magnitude of the rest. From out of ; 
this chaos the caiion gradually emerged, widening out and 
approaching more to the extent and appearance of a narrow 
valley. The south side first began to break away with | 
sloping bluffs, covered with cactus and stunted vegetation, — 
while the north side continued perpendicular for three mil 
and a half beyond the second “narrows,” where it joined be 
huge mountain of igneous formation, consisting of six basaltic 
terraces one above the other, which formed a fine landmark 
for miles around to show the position of the cafion. Beyon 
this are foot-hills on both sides for two miles more, when 
cafion- merges into the widening valley, which, some si 
miles further on, joins that of the Rio San Pedro just sou 
of Camp Grant. In this valley nearly all the water of t 
at the fort, that for many weeks during the year no s 
water whatever enters the Rio San Pedro from it, altho 
in the cafion there is always a fine stream. 
An Indian trail, which is easily followed in single fil 
except where the bed of the stream alone is left, or whe 
the whole path is blocked up with débris, leads quite through 
the gorge. In the first part of the cafion there are at least 
five lateral means of exit through arroyos which enter it, one 
on the southern and four on the northern side, but there 
no escape whatever for the rest of the way. 
Some of our men in advance came one day across an Indi 
encampment, in which the ashes of a fire were still smoki 
but nowhere did we see an Indian. Their wigwams were 
of very frequent occurrence during the last eight or ten miles, 
especially in the valley between the cafion and Camp Grant. 
