— "m" 
GRAND RIVER VALLEY, SOIL AND CLIMATE. 59 
at night with wagons without a road. We encamped, therefore, without grass, near the dry 
bed of what proved to be a small intermitting creek of bitter water. Streams of this kind during 
the day time, in the dry season, contain no water, but small rivulets break out and flow during 
the night, and again disappear as the sun becomes hot. So many of our animals gave out, 
that several of the wagons did not reach camp during the night. 
e were here about four miles from the river, which, by following the ravine cut through the 
cafion wall by the creek, was easily reached on horseback, (and only obstructed for wagons by a 
dry channel cut deep in the clay,) at a narrow bottom of fine grass two or three miles in length, 
with shady groves of cotton-wood on the banks of the stream. The red sandstone cañon walls 
are nearly vertical, and two hundred feet high; beyond which smaller ledges rise above each 
other, terrace-like, for some miles towards Salt mountain, which bears south from our camp, 
some twenty miles beyond the river. The cafion narrows to the width of the river below the 
groves of cotton-wood. In a ravine by which Captain Gunnison approached the river, four miles 
below Salt creek, and nearly opposite the mouth of the San Miguel, he says, **sandstone and 
clayey deposits alternate one above the other, one layer of which is altered by heat, and much 
of the argillaceous rock is black with the appearance of coal having burnt under it. Coal is 
found in the cafion near our camp, and can be gathered in place, and there can be no doubt of 
this being a part of the Green river coal basin formation; at least, the formation has the same 
appearance there as here, and the water from the red sandstone and clay deposits similar crys- 
tallizations." 
We observe the greatest contrast between the heat of the days and nights in these mountain 
valleys; the thermometer from noon to 3 o'clock p. m. ranging, for the last several days, from 879 
to 92° Fahrenheit, and at night falling below the freezing-point. Yet we find a cactus here which 
flourishes generally in Texas and warm climates. 
The barrenness of these valleys is greatly influenced by the alkaline and saline ingredients of 
the soil, while their dryness is easily understood by observing the distribution of the aqueous 
vapors. The moment a cloud begins to form, it rushes towards a mountain chain, is poured 
in torrents upon its highest peaks, and rushes down its rocky sides into the chasms and gutters 
in which the beds of streams lie in the valleys, too deep and confined to irrigate the adjacent 
lands to any distance. The higher mountains are also protected by the clouds to a great extent 
from the powerful rays of the sun, which scorch the valleys; and hence, in inaccessible places 
to man, grass and herbage flourish. It is not intended to say that no rain falls upon the valleys 
and plains, but only a very small proportion is deposited there during the warm season, when 
the rain comes in showers of sudden formation; but in the colder parts of the year more is dif- 
fused over the general surface. We have seen rain falling in showers usually in the afternoon, 
on the mountain-tops, almost every day since we first came in sight of the Rocky mountains, 
two months since; whilst in this valley for two weeks we have been scorched at midday by a 
tropical sun, and in the whole distance scarcely moistened, except once or twice, near the sum- 
mits of passes, by rain. 
The formation of the valleys is against a system of artificial irrigation; their absorbing power 
being so great that the mountain streams, during the summer, seldom reach far into the plains. 
It is therefore only at the foot of the mountains which are not too elevated and cold for vegeta- 
tion to flourish, where the small streams descend, that irrigation can be employed. No part of 
the route thus far from San Luis valley, therefore, offers a spot of any considerable extent suita- 
ble for settlement. Sufficient grass flourishes in the mountain valleys of Grand river, east of the 
junction of the Blue, for grazing purposes; but it is a significant fact, bearing upon the climate, 
that elk frequent them only in the summer, migrating both to the north and south in autumn, 
where they remain during the winter, and again return in the summer. 
Leroux, with three companions, left us at this camp to return to New Mexico, having completed 
his engagement as guide. He expects to travel much at night, and trusts to his tact and knowledge 
