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 he sand hanks, 3 

 to 5 feet high, which have drifted and collected round the stems of mesqulte ; but observation 

 shows that those shrubs have grown there when the bank 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 bank is 30 feet above the well, which is here 

 in a bed similar to that at Alamo ; there is but 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, but 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 efi"ect, 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 G-ulf, 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 Gulf, 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 outliue, 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 



