Exploitations and Surveys for the Pacific Railroad. 87 



nel three-fourths of a mile long, at an elevation not less than 

 8,000 feet, is required, when the descent is made to the Zuni 

 river and near the Pueblo of Zuni. The route then crosses, over 

 undulating ground, to the Puerco of the West, at the Navajo 

 spring. 



Another route across the Sierra Madre, about twenty miles 

 farther north, was examined by Mr. Campbell, which is far more 

 favorable. The height of the summit is about 6,952 feet above 

 the sea and it is passed without a tunnel [as stated in a subse- 

 quent Eeport of Capt. A. A. Humphreys, U. S. Topog. Eng.] 



The Puerco of the West heads in this pass, and the route 

 follows the valley of this stream, (intersecting the other line at 

 Navajo spring,) to its junction with the Colorado Chiquito ; then 

 the valley of that stream to the foot of the southeastern slopes 

 of the San Francisco mountains, (112° W.) elevation 4,775 feet ; 

 distance from Fort Smith 1,182 miles, and from the crossing of 

 the Kio Grande 328 miles. Here it ascends to the dividing 

 ridge between the waters of the Gila on the south, and of the 

 Colorado of the West on the north, and continues (or nearly 

 so) upon it for about 200 miles, to the Aztec Pass, elevation 

 6,281 feet ; distance from Fort Smith 1,350 miles. The highest 

 point reached upon this undulating ridge is 7,472 feet, at Le- 

 roux's spring, at the foot of the San Francisco mountain. From 

 the Aztec Pass, the descent to the Colorado of the West is made 

 by a circuitous route northward along valleys of its tributaries, 

 the largest and last being Bill Williams's fork, the mouth of 

 which, on the Colorado, is 1,522 miles from Fort Smith, and at 

 an elevation above the sea of about 208 feet. 



The Colorado is now ascended 34 miles, when the route, leav- 

 ing it at the Needles, follows what was erroneously supposed to 

 be the valley of the Mohave river, but which proved to be the 

 valley of a stream, dry at the time, whose source was in an 

 elevated ridge, which probably divides the Great Basin from 

 the waters of the Colorado. The summit having been attained, 

 at an elevation of 5,262 feet above the sea, the descent is made 

 to Soda lake, the recipient at some seasons of the waters of the 

 Mohave river, 1,117 feet above the sea, with an average grade 

 of 100 feet to the mile for 41 miles — the steepest grade yet re- 

 quired on this route. From Soda lake, the ascent to the summit 

 of the Cajon Pass, elevation 4,179 feet, in the Sierra Nevada, is 

 made by following the valley of the Mohave river. The summit 

 of this pass, by the line of location, is 1,798 miles from Fort 

 Smith, and 242 from the point of crossing the Colorado. Here 

 a tunnel of 2-J- or 3 T 4 ¥ miles through white conglomerate sand- 

 stone is required, descending to the west with an inclination of 

 100 feet to the mile, which grade will be the average for 22 

 miles into the valley of Los Angeles, if the broken character of 



