24 POOLE'S SURVEY FROM SAN DIEGO TO FORT YUMA. 



The wide valley into which the creek enters offers superior advantages over the basins of 

 Vallecitas and Cariso creek, and has a great resemblance to that of San Felipe, the mountain 

 slopes sjjreading out at their base forming broad inclined planes highly favorable to the location 

 of the road. The channel of the water course has an inclination of about 60 feet per mile, to 

 a narrow jjass or gorge formed by the projection of a rocky spur a distance of 17.4 miles. The 

 elevation of the track at the mouth of the caiion, as proposed, will increase the rate of descent 

 to about 80 feet per mile. 



Immediately after passing the gorge the open plain of the desert appears to the view, bounded 

 on the right by the mountains of the peninsular range leading into Lower California. On the 

 left and north the spurs from the same range are seen overlapping en echelon as far as the eye 

 can reach. By skirting the mountains on the right any desired elevation for the track can be 

 adopted, and will ensure the avoidance of the patches of drift sand which are sometimes 

 encountered on the lower plain. 



From the gorge the proposed line runs along these foot hills to the base of a high mountain 

 12.20 miles distant therefrom; then descending gradually to the plain in nearly a southeast 

 course, it passes over a broad level flat of blue clay for 10.8 miles, when it reaches the arroyo 

 of Cariso creek, which is always dry at this point. Crossing this channel we traverse the wide 

 plain with scarcely an obstacle for 20 miles, and come to the deep channel of New river. Here 

 water can be obtained by digging, and by the sinking of artesian wells an exhaustless supply 

 can doubtless be procured. 



From New river to a point a few miles north of Cook's wells, where the lofty sand ridges 

 from the north terminate, the route will have a nearly uniform and slightly ascending grade 

 over alternate sections of hard clay, loose gravel, and beach sand with pebbles. About 18 miles, 

 in a direct line, brings the line to the mouth of the G-ila, by keeping to the north of Pilot 

 Knob and traversing tlie table land or upper terrace bordered by the sand hills of Cook's wells. 

 The entire distance from San Diego, by this route, is 189.10 miles. 



It is now demonstrated beyond doubt that no route across the desert can be carried to the 

 northward of the point near Cook's wells above indicated. 



My surveys of the United States public lands during the present year, tinder the orders of 

 the Surveyor Jeneral, show the existence of an extensive range of lofty sand hills or drifts rising 

 from the plain to the average height of 350 feet, and from one to two miles in breadth Their 

 direction is nearly northwest from Cook's wells, and they are terminated only by the desert 

 range of mountains on the north, which are 50 miles distant. This singular obstacle, unlike 

 the smaller detached sand hills of the neighborhood, seems to be entirely composed of drift sand, 

 and is not, like other sand ridges, based upon a terrace or bank of earth. The ground on both 

 sides of it is about at the same level, and is divided into two basins, which receive the drainage 

 of several hundred square miles of territory. It was observed that the direction of the wind on 

 the west side of the ridge was constantly from the northwest, while on the east side it blew from 

 the north and northeast down the valley of the Colorado. Whether these winds are the cause 

 of its formation is not a matter for present discussion ; but the fact is plain that they oifer a 

 permanent obstacle to the construction of a railroad. It is evidently necessary to turn this 

 barrier by passing to the south of it, where it subsides into the general level of that part of the 

 desert. 



