ELEVATION OF MOUNTAIN PASSES. 115 



As Fulton, El Paso, and San Diego, in California, are nearly in the 

 same direct line, and one which intersects the longitudinal axis of the 

 continent at right-angles, a road connecting these points would form 

 the shortest line of communication to the Pacific in this latitude, and 

 would pass near the valley of the Gila, or its vicinity. 



The direct line of this road prolonged eastwardly from Fulton 

 would pass through Arkansas, and intersect the Mississippi river a little 

 below Napoleon, opposite the State of Mississippi, and would traverse 

 a section which presents no serious impediment to the passage of a rail- 

 road. 



This route was surveyed in 1851 by Mr. Sidell, (civil engineer,) under 

 the direction of the Topographical Bureau, and resulted in perfectly 

 establishing the feasibility of the route, and the determination of the fact 

 that the most elevated ground between Lake Providence and Fulton (a 

 distance of two hundred miles) is but one hundred and sixty feet above 

 the flood water-table of the Mississippi, and only one hundred feet above 

 that of Red river. 



The terminus of the eastern section of this route upon the Del Norte, 

 could be resumed upon the west bank of that stream ; and if the practi- 

 cability of constructing the road down the valley of the Gila can be 

 established, it would give a continuous line to the Colorado river. 



Although our knowledge of the country west of the Rio Del Norte is 

 for the most part confined to a few traces that have been pursued by 

 travellers making their way to the Pacific ; yet it is believed that suffi- 

 cient reliable data may be deduced from competent authorities to war- 

 rant the expectation of finding a route with admissible grades, as far, at 

 least, as the Colorado. 



Before reaching the waters that flow into the Pacific, it becomes 

 necessary upon this route, as upon all others in our territory, to surmount 

 the Rocky mountain chain. The elevation of the crest of this great 

 continental vertebral column varies from five to seventeen thousand feet 

 above the tide-level of the ocean, but has a declension towards its south- 

 ern extremity, which greatly favors the project in question. The baro- 

 metrical measurements which have been made, place " Long's Peak" in 

 latitude 40° 36' at the maximum, and the culmination of a pass or defile 

 in near latitude 32° at the minimum altitude. 



The elevation of the eastern base of the mountains in latitude 42° is 

 the same as the summit of the range in latitude 32°. The elevations of 

 other passes that have been examined, vary from seven to eight thou- 

 sand &iet above tide. 



If, so far as the economy of railway transportation is concerned, the 



