EXTRACTS FROM [PRELIMINARY] REPORT. 27 
The distance from the ‘‘ Needles”” to the pass is about ninety miles. Cutting thirty feet 
at this summit, we have an uninterrupted descent for fifty-six miles (following the detours of 
a great valley) to Soda lake, an immense dry and sandy basin, in which the Mohave loses its 
waters at a maximum rate of only seventy-five feet per mile. 
From Soda lake to the point on the Mohave at which the Spanish trail leaves that river, a 
distance of ninety miles, the average ascent of the stream is but eighteen feet per mile. 
Leaving the river near this point, a route is practicable up the dry gullies which lead to the 
summit of the Cajon Pass, at the wagon road, the narrowest point of the divide: the distance 
to the pass is twenty-four miles. For nearly twenty miles the maximum grade will be about 
sixty feet per mile; thence through the divide by a tunnel of two and a half miles, (rock, 
white conglomerated sandstone,) and grade of ninety feet per mile. A more favorable approach 
to this pass is believed to exist at the head of the Mohave, close under the San Bernardino 
mountain. 
The stream which heads in the Cajon Pass, and flows to the Pacific, is very rapid in its 
descent; but the slopes on the right bank are regular, and are broken but in few places by 
narrow gorges of tributary streams. This being the case, by descending with a grade of one 
hundred feet per mile for about twenty miles—keeping up on the slopes of the mountain, 
, passing, by means of a short tunnel or heavy cutting, the salient spur which forms the right 
bank of the stream below—the valley of Los Angeles is reached. From the foot of this grade, 
keeping upon the slopes, for twelve miles the grade is lessened to sixty-three feet per mile. 
This point is about half a mile east of Cocomongo rancho ; thence to the crossing of the Rio San 
Gabriel, near the village of Monte, thirty miles, with a maximum of thirty-eight feet per mile ; 
thence to the city of Los Angeles, with about the same light grade, or from the Monte to 
the port of San Pedro, thirty miles, with a descent of about twelve feet per mile. 
To make a minute estimate of the probable cost of a railway from the Mississippi to the 
Pacific cannot come within the province of this exploration; it being well known that, for 
such a purpose, the most accurate and detailed measurements are required. The barometric 
observations, however, have developed a most interesting profile, and are sufficiently reliable 
to determine the great question of practicability beyond a doubt. There are but three points 
on the entire route explored at which the work may be said to be difficult ; these are the Pecos, 
the Cañon de Carnuel, (at Albuquerque,) and the Cajon Pass in the Sierra Nevada. 
And these sections will not differ by a comparison with the Baltimore and Ohio railroad 
from Cumberland to Wheeling, or any of the railroads which cross the Alleghany mountains, 
in point of grade, curvature, and boldness of graduation, "There is but one point on the route 
where it will be necessary to employ less than a 1000 feet radius; this point is in Striped 
Cañon, on Bill Williams’ fork. 
In conclusion of this hasty statement, I desire to state that the few hours taken at intervals 
from the calculations and arrangements for the barometric profile, and the superintendence of 
and plotting of the topography on the general maps, have not been sufficient for a full consid- 
eration of this important matter; it is due, therefore, that proper allowance be made for its 
hastiness. 
Respectfully submitted : 
ii ALBERT H. CAMPBELL,. 
Engineer and Surveyor. 
Lieutenant A. W. WHIPPLE, 
| United States Topographical Engineers, 
In charge of exploration for a railroad route near 35th parallel. 
* * * * * * * M. 
