CHAPTER XV. 
MOJAVE RIVES VALLEY- 
Santa Fe trail to salt lake.—Mojave river and vallet.—Cajon pass.—Primary rocks of.—Mica slate and por¬ 
phyry.—Pink sandstones.—Local drift.—Limestone in.—Thick conglomerate and sandstone of the eastern 
slope.—Second axis in the pass.—Probable thickness of the conglomerate.—Distinction between them and the 
PINK SANDSTONES.-SLOPE TOWARDS THE MOJAVE.-NATURE OF THE SOIL UPON.-VEGETATION OF.-YuCCA, CEDAR, ARTE¬ 
MISIA.-SOAKAGE OF THE RAIN WATER THROUGH THE SANDSTONES.-WELLS NEAR THE RIVER —COURSE OF THE RIVER 
WHERE FIRST REACHED.-DIFFERENT TEMPERATURES OF AIR, WELLS, AND THE RIVER.-HlLLS EAST OF THE MOJAVE.-FER¬ 
TILITY OF MOJAVE VALLEY.-HEAT OF THE SOIL DURING THE DAY -SIMILARITY OF THE FLORA WITH THOSE OF LOS ANGELES 
valley.—Amygdaloid range along the mojave sixty-six miles down.—Metamorphic action exerted on the sand¬ 
stones.—Variety in the volcanic rock—Felspar dykes.—Accompanied by gypseous veins.—Granitic chain 
CROSSING THE RIVER FURTHER DOWN.-SoDA LAKE, ITS LENGTH AND FORM -APPEARANCE OF THE SURFACE.-SALINE COAT¬ 
ING OF THE SURFACE.-QdCKSAND BOTTOM.-SuBSOIL SOAKED WITH WATER.-INTRUSION OF A DYKE UPON THE PLATA.- 
Primary limestone —Aspect of the playa.—Mirage—Origin of the saline incrustation of the pi.aya.—Fresh¬ 
ness OF THE RIVER WATER.-RECAPITULATION.-CHARACTERS OF THE COUNTRY EAST OF THE SlERRA NEVADA.-APPEAR¬ 
ANCE OF THE VALLEYS.-SLOPES OF THE CONGLOMERATE.-DIFFERENT LEVEL OF SODA LAKE AND THE COLORADO RIVER.- 
Direction and nature of the mountain ranges.—Number of ranges between soda lake and the sierra —Inter¬ 
vals BETWEEN THE CHAINS.-FALL OF RAIN.-LIMITED FERTILITY OF THE DISTRICT.-NUMBER OF ANIMALS SACRIFICED 
FROM DROUGHT.-EXPOSURE OF THE HIGH PLAIN TO WINDS.-COLD OF NIGHTS- DeW. -THUNDER STORMS WITHOUT RAIN.- 
Parallelism of the geological forces.—Plain reaching across the Colorado to the pimas villages.—Saline 
INCRUSTATIONS AT SODA LAKE.-CHEMICAL EXAMINATION OF.-INCRUSTATION AT NAVAJO CAMP. 
The old Spanish trail from Los Angeles valley to Santa Fe entered the great basin from the 
Pacific slope by the Cajon Pass, followed the course of the Mojave river for several miles to the 
northeast, and then left its he'd to take a more northerly direction toward Salt Lake. This trail 
is now followed to the latter place by the mail carriers in their fortnightly journey to Salt Lake 
City, and by the Mormons in their intercourse between that city and the Mormon settlement in 
San Bernardino valley. 
The Mojave river is first struck by the trail not far below its sources—its further course from 
the point where the trail leaves it was hut partially known; to clear this obscurity was the 
object in crossing the Cordilleras to enter this, the second lowest steppe of the Great Basin, to 
ascertain whether the river emptied itself into the Colorado or was lost in the basin ; a very 
hasty reconnaissance was made by striking the river at the east slope of the Cordilleras, and 
travelling down its bed until it was lost in the alluvial sands of the small basin of Soda lake. 
While crossing the Cordilleras through Cajon pass its geology was observed, and is noted in 
this section rather than in the chapter on the Cordilleras, to understand the constitution of 
which it may be necessary to refer to this description of the pass. 
Cajon pass lies behind (eastward of) Kikal Mungo hill, and between it and an elevated flat- 
topped range, which is the northern extension of the San Bernardino mountain. 
The general direction of the pass is north by west and south by east, and as the strike or axis 
of the range is here about south 70° east a good section is obtained in ascending the pass. Here, 
also, as in many other mountain ranges, it may he observed that the geological axis itself is not 
situated at the most elevated point of the pass, for while the axis is on the south and west 
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