40 | DESCRIPTION OF THE COUNTRY. 
sary to thread both of the other passes mentioned. The latter—the Taheechaypah—is in latitude 
35° 7’, and from its summit, slopes of gentle inclination lead eastwardly across the Great Basin 
to the northwest bend of the Mojave river. In this consists one of the advantages of the route 
by the 35th parallel, viz: that by a single pass—the most available known—the Cordilleras of 
California are surmounted, and San Francisco reached with the least practicable deviation from 
a straight line. Therefore, we are enabled to adopt San Francisco as the termination of this 
route, and to disregard the difficulties which would have been encountered at Cajon Pass in 
obtaining an entrance to the valley of Los Angeles. 
The central portion of the region embraced in this section of our route is noted for barrenness. 
Some of the soil possesses the elements of fertility, but vegetable growth is prevented by the 
want of moisture. As before stated, the vapor rising from the Pacific is generally precipitated 
upon the western slopes of the mountain chains that traverse the State of California, nearly 
parallel to the coast. At their eastern bases are found a few springs, and small streams flowing 
towards the desert; but, excepting the Mojave, they disappear at a short distance from their 
sources. Between the mountains and the Colorado the climate is drv ; the winds parch the 
earth, and the soil is arid. No part of our country has a wider celebrity for barrenness than 
that known as the Californian desert, between Cariso creek and Rio Colorado. Until theautumn 
of 1849, it was found to be a sandy and dreary jornada, without water or grass for about 
80 miles, causing great suffering to the overland emigrants who attempted to cross it. Then, 
suddenly, water appeared in various lagunas and channels; and in a few weeks the central 
portion of this desert was covered with large fields of luxuriant grass. The water was probably 
backed up by a strong south wind upon the Gulf, and a simultaneous rise of the Colorado river 
had the effect of irrigating the soil of the desert basin. At length, by evaporation and absorp- 
tion, the water disappeared ; and a spot that had given evidence of remarkable fertility became 
naked as before, without the faintest trace of vegetation. 
There are peculiarities in the conformation of the country, near the parallel of 35°, requiring 
some modification of the general characteristics above described. The sudden breaking down 
of the Sierra Nevada, near that latitude, probably allows a passage for a portion of the moist 
air from the coast, sufficient to nourish nutritious grasses upon the prairie slopes, and, by pre- 
cipitation upon the San Bernardino range, to feed the Mojave river. Upon the elevated ridge 
between Soda lake and the Colorado, there is also a deposition of moisture sufficient to sustain 
a few small springs, and give sustenance to grama grass upon its broad slopes. The Mojave 
river, from its source to the entrance into the basin of Soda lake, irrigates a valley which con- 
tains a belt of arable soil. From that point to the western slope of the Paiute mountains, 
with the exception of a narrow space in the vicinity of the lake, the country is sandy and barren, 
possessing all the characteristics of a desert. 
The valley of Rio Colorado affords a large extent of fertile bottom-land which may be irrigated 
and cultivated. The soil is believed to be superior to that of the Rio Grande. Large patches 
of it are cultivated by Indians, producing crops of maize, wheat, beans, melons, and squashes. 
As artificial irrigation seems to have been but little resorted to by the natives in their system 
of agriculture, it may be inferred that there is much moisture in the atmosphere, or that summer 
rains are more frequent here than in New Mexico. With a suitable system of acequias, or 
drains from the river, to water the soil, this valley would doubtless be as well adapted fór the 
production of tobacco and cotton as the bottom-lands of Rio Gila, near the Pimo villages. The 
southern portion seems favorable for the production of rice and sugar. 
The amount of arable land upon the Colorado, between the parallel of 35? and the junction 
of Rio Gila, is roughly estimated at 700 square miles. This estimate is based, partly upon our 
own observations, but mainly upon the results of Captain Sitgreaves’ survey, with measure- 
ments taken from his map, and is made up as follows, viz: the Mojave valley, forty miles in 
length, averaging four miles in width, equal to 160 square miles; the Chemehuevis valley, 
eight miles in length, averaging four miles in width, equal to thirty-two square miles ; the 
