LEAVING SAN LUIS VALLEY. 
45 
August 30.—Leaving camp we reached Sahwatch spring and butte, by a very direct course 
across the valley, in ten miles and a half. This spring of pure cold water bursts from the base of 
the granitic butte which is immediately west of it, but detached from the Sahwatch mountains, to 
which it properly pertains. Captain Gunnison observed, on the 31st of August, large volumes of 
air at intervals escaping with the water of this spring. This butte is not high, but its isolation 
makes it a prominent feature, standing as it does at the puerta or gate of the Coochetopa Pass. It 
is formed of coarse, gray granite rocks. The spring sends out a fine little stream, winding south 
and east along grassy fields until it joins the Sahwatch creek, which we reached five miles from 
the butte in the broad opening leading to the Coochetopa Pass. This stream, which is said to 
sink before reaching the Rio Grande, flows past our camp over a pebbly bed. It is one foot in 
depth and eighteen in width, with a rapid current. Its valley at this point is five or seven miles 
in width, growing narrow towards the west; and there are several isolated buttes standing in it, 
but none of them of considerable height. A few cotton-wood trees and a margin of willow 
bushes line the stream. The soil passed over to-day was unusually light and dusty, our horses 
sinking hoof-deep in it over large spaces. 
We here leave the immense valley of San Luis, which is one of the finest in New Mexico, 
although it contains so large a proportion of worthless land—worthless because destitute of water 
to such an extent where irrigation alone can produce a crop, and because of the ingredients of 
the soil in those parts where salts effloresce upon the surface. Its lower portion is adapted to the 
cultivation of grain, as we have seen at the Costilla and Rio Colorado; and, if its upper part 
should prove too cold for cereals, its fine fields of grass on and above the Rio Grande del Norte, 
must make it valuable for grazing. Elevation above the sea 7,567 feet. 
August 31.—Five miles from camp the valley narrowed to a few hundred yards in width, 
and continued so for most of the day’s travel of twelve miles. At our camp this evening it is 
half a mile wide, covered with fine grass, fine bottoms of which we passed several times during 
the day. We passed, also, a fine grove of cotton-wood half a mile in length, in which deer 
were bounding about in every direction, even passing between our wagons, which were separated 
by but a few yards. When ten miles from our morning camp the. sand-hills in front of Williams’ 
Pass lay plainly in sight, directly down the valley. We then changed our direction, taking a 
course for a short distance south of west, on which we are encamped. The hills and mountains 
enclosing this thus far beautiful valley, vary in height from two or three hundred to twelve or 
fifteen hundred feet, covered with a scanty growth of small pine. No mountain pass ever 
opened more favorably for a railroad than this. The grouse at camp are abundant and fine, 
as are also the trout in the creek, several having been caught this evening weighing each two 
pounds. 
On the morning of the 29th instant Captain Gunnison, and Mr. Homans, accompanied by a guide 
and four or five men, left the main body of the party and continued up the San Luis valley fey four¬ 
teen miles to its head, where a small park, into which several small streams flow and unite, forming 
a single creek, is nearly separated from the main valley by low hills extending from the mountains 
on either side, into the plain. To this park, which is ten miles in width by fourteen in length, as 
well as to the creek flowing from it, Captain Gunnison gave the name of his assistant, Mr. Homans, 
who located them. In this park the party crossed a narrow strip of alkaline earth, sparsely covered 
with grease-wood, to the most luxuriant fields of grass seen on the trip. This grass covers an 
area of ten miles by four. Captain Gunnison says, “ this is the prettiest, best watered and grassed 
valley, with wood convenient for fuel, that I have seen in this section. Much hay could be cut, and 
fine grazing farms opened; and it is also probable that wheat and flax, and perhaps other grains, 
could be raised.” From this park the party proceeded over a pathway of coarse, angular gravel, 
formed by the crumbling of the quartzose rocks of the hills, by an inclined plane, to the summit 
of the pass—the object of its present examination—which here divides the waters of the Arkansas 
river from those of the Rio Grande del Norte. At 1.45 p. m., August 30th, on this summit- 
