54 REMARKS UPON THE PROFILE. 
rials for the construction of bridges, roads, and houses ; there are also very beautiful marblen, red 
porphyry, and especially, I think, will be found geg, mines rich in silver and gold.”” 
Having reached the foot of the Pacific slope of the mountains, the route to Los Angeles and 
San Pedro passes over an alluvial soil. Quarries of stone may be obtained upon the mountain 
slopes, not far distant from the trail. 
Between Los Angeles and San Diego—but near the latter place—there are veins of coal. 
They were first discovered, I believe, by Captain Warner, of the topographical engineers, 
while making examinations of this country, in 1848. When I visited the place in 1850, several 
veins were found upon the surface, from an inch to an inch and a half in thickness, which 
afforded specimens of coal believed to be moderately good. Shafts had been dug, bw aban- 
doned on account of the small quantity of mineral obtained. Lately, it has been stated* that 
“a bed of good coal, sufficiently thick for working purposes, has been opened. A shaft has 
also been run down, piercing several small strata from 16 to 20 inches thick." Bitumen also 
is found. in considerable quantities upon the coast. Near Los Angeles, there are large pits of 
petroleum, which will doubtless prove to be of some value as an article of commerce. 
THE PROFILE. 
After it has been determined that the natural resources of a country are of such a character 
as to afford facilities for the construction of a railway ; that an adequate portion of the adjacent 
territory is susceptible of cultivation, and suitable for settlement ; that materials for construction 
can be procured within the requisite distances, and permanent supplies of fuel and water insured 
at necessary points,—there remains the question of grade: 1st, as regards practicability ; and 
2d, economy. An examination of the country with the usual reconnoitring instruments—ascer- 
taining the positions and heights of various points at considerable distances from each other— 
will, generally, be sufficient to determine the former. For the latter would be required a care- 
ful and minute survey of the whole line. Hence, in order to form an idea of the comparative 
advantages of different routes, general profiles are insufficient. "The stations where altitudes 
are taken being at long intervals apart, the differences of altitude of these stations may be small ; 
and, supposing that they can be connected by a uniform grade, a route represented may appear 
favorable ; yet the intermediate minor ascents and descents may be so numerous and difficult, and 
the amount of cutting and filling required so great, that, where the line is of great length, the 
cost of the construction of a railroad would exceed practicable limits. The general profile of an- 
other route may present greater ascents and descents, and heavier grades ; while the surface of the ` 
ground between the barometric stations is smooth, and the slopes are continuous and uniform, 
so that the cost of grading would be vastly less in the latter case than in the former. To form, 
therefore, a satisfactory conclusion in regard to the advantages of any proposed line, there is 
required more detailed information in regard to its topography than can be gathered from a 
profile showing only the grand general slopes, and the aggregate of their ascents and descents. 
The country to be explored was of such extent, and the time so limited, that the field opera- 
tions were necessarily hurried, and devoid of that accuracy which would have been desirable. 
In order, however, to give to our operations as nearly as possible the character of a survey, very 
numerous and frequent observations were made to determine the elevations and depressions 
along the line, and two complete sets of field sketches taken: the one exhibiting the general 
features of the country, and the other the special topography in the vicinity of the route 
traversed. From these have been constructed a series of topographical maps, on a scale of 
soloo, delineating in detail a considerable portion of the profile trace. As the value of these 
maps depends upon the correctness of the altitudes given, it will be necessary to allude more 
fully to the method by which they were obtained. 
See Railroad Record, page 274. 
