CHAPTER XV. 



MOJAVE RIVER VALLEY- 



Santa Fe trail to salt lake. — Mojave river and valley. — 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. — I'robable thickness of the conglomerate. — Distinction between them and the 

 pink sandstones. — Slope towards the mojave. — Nature of the soil upon — Vegetation of. — VcrcA, cedar, Arte- 

 misia. SoAKAGE of the RAIN WATER THROUGH THE SANDSTONES. WeLLS NEAR THE RIVER. — CoURSE OF THE RIVER 



WHERE FIRST REACHED. DIFFERENT TE.MPERATURES OF AIR, WELLS, AND THE RIVER. HiLLS 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 dow.n. — 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. QuiCKSAND BOTTOM. SuBSOIL SOAKED WITH WATER InTROSION OF A DYKE UPON THE PLAYA. 



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 Sierra 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 



FRO.M 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 exami.vation of. — Incrustation at navajo camp. 



The old Spanish trail from Los Angeles valley to Santa Fe entered the great basin from tlie 

 Pacific slope by the Cajon Pass, followed the course of the Mojave river for several miles to the 

 northeast, and then left its bed 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 but 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 tlie 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 be 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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