124 
COLORADO DESERT-NEW RIVER. 
the road, and is alternately a sandy and clayey floor. The sand along this route appears to 
have drifted in heaps over raised clay mounds ; these, at first sight, appear to be sand hanks, 3 
to 5 feet high, which have drifted and collected round the stems of mesquite ; hut observation 
shows that those shrubs have grown there when the hank was at that upper level, or nearly so, 
and while these hanks are sand above they are mainly clay below ; their formation is more due 
to water than to wind. At Cook’s well the terrace hank is 30 feet above the well, which is here 
in a bed similar to that at Alamo ; there is hut one well or spring, 4 feet across, and having 
water in it about 3 feet deep-; its taste is clayey and slightly hard ; the well does not refill 
readily and requires to be deepened. As the soil is more moist here than at Alamo, a shaft 
sunk to a depth of 20 feet ought to afford a bountiful supply of water. 
The mesquite between these two waters was flourishing, and, about Cook’s well, in pod and 
very abundant. Yet there were passed groves of cotton-wood trees which were standing, but 
dead ; some few had fallen, hut were, owing to the dryness of the air, but little decayed. The 
scene presented the curious anomaly of one class of trees flourishing in the immediate vicinity 
of the dead trunks of another species. To what change of local conditions could this be due? 
Some have believed in the elevation' of the soil, by which it became too dry to sustain these 
water-loving trees. But while the proofs of elevation are general, there is no local evidence to 
support this view ; besides, at higher levels at present, that is, at Alamo Mocho, a few flourish¬ 
ing cotton-wood trees exist. The cause, like the effect, is no doubt local, and may be attributed 
to the lessened supply of water from the Colorado river reaching this point. 
The belief that the waters of the Colorado have only recently flowed into and formed New river 
is evidently an erroneous one ; a single fluviatile eruption could not have formed the deep and 
well worn trough which is displayed at the Alamo. At the present time, the lower stratified 
sands of the desert are water-soaked by the Colorado river ; the wells at Indian wells, (not 
visited,) at Alamo, and Cook’s well, are the waters of the Colorado filtered through, and at no 
remote period that river may have, at the time of freshets, annually rolled its waters through 
New river bed. The Colorado, from the point where.it leaves Fort Yuma until it debouches 
into the Grulf, resembles, to some extent, the Mississippi; it changes its banks by washing them 
away, and it forms levees for itself, so as to become higher than the vicinity ; an increased 
freshet, or an obstruction to the flow of the water by a south wind in the (/iilf, may so raise the 
river level as to overflow or remove its banks and flood the adjacent lands. Cook’s wells may 
have been from some such cause, until very lately, supplied with a much larger amount of 
moisture, which enabled the cotton-wood trees to grow on the desert level,.and the sudden with¬ 
drawal of which may have been the cause of their death. 
By such occasional overflows of the river upon this district may have been formed the rounded 
patches of clay, covered with sand, resembling “domes” in miniature, to which reference has 
been made. 
From Cook’s well to the Colorado the trail slowly descends off the terrace bank to the river 
edge. At Algodones is an Indian built village beside some low sand hills, which here lie at 
the margin of the river ; along this trail an elevated terrace continues on the left hand (or north¬ 
east) the whole distance to Fort Yuma ; it is more than 30 feet high, is covered up by drifted 
sands which round its outline, but it presents very much the appearance of an ancient river line 
or bank. 
At Algodones, a slight elevation of porphyry pebbles, cemented by argillaceous and^ 
