Vol. 6] Baker: Cenozoic History of the Mohave Desert. 



355 



Sierra slope. It does not cleave into strata, but the direction of bedding 

 is conspicuous in the exposures, and different layers weather so unequally 

 that the whole is carved into a series of escarpments, the faces of which 

 are beautifully fluted by rain. The thickness exceeds 400 feet. Nos. 2 

 and 4 are basalts, 30 and 50 feet respectively in thickness. No. 3, 100 

 feet; No. 5, 200 feet; and No. 7, 100 feet, are like No. 1, but more coher- 

 ent, the cementing material being insoluble in acids. No. 6, 100 feet 

 thick, is a homogeneous, pale pink, volcanic tuff, containing all the con- 

 stituents of the adjacent sands, with the addition of pumice and a 

 definite matrix. No. 8 is a sand like No. 1, but well cemented by oxide 

 of iron. No. 9 is an orange, massive, subspherulitic rhyolite, and No. 10, 

 a massive fine-grained compound of hornblende, pyrite, and a feldspar. 

 The two, whose correlation was not made out, constitute the spur of the 

 range and wall the canon for a half mile. Beyond them the sands are 

 resumed (11) with the same dip, but their relation was not established. 

 The line of section, produced eastward, would reach out on an open 

 desert — that in which is the Desert Wells stage station. 



The chief interest of the section lies in the close relationship of the 

 sand beds to the intercalated tuff. The latter is a product of eruption, 

 endowed with a light vesicular paste, and separable by no sharp line 

 from typical lavas. The former is so closely affiliated to the tuff, on the 

 one hand, and to the ordinary desert detritus on the other, that we are 

 left in doubt whether it was transported and distributed by volcanic or 

 by meteoric waters. 



Fairbanks 13 was the next geologist to visit the Red Rock 

 Canon locality. He describes the sediments there as follows : 



. . . On the northern slope of the El Paso Eange, between Mojave 

 and Owen's Lake, there is a series of beds of clays, sandstone, volcanic 

 tuffs and interbedded lava flows. These are probably 1000 feet or more 

 in thickness and extend over a considerable area between the El Paso 

 range and the Sierra Nevadas. On the north and northeast they pass 

 beneath Salt Wells valley and the wash from the Sierra Nevadas. They 

 are finely exposed in Eed Rock Canon and about Black Mountain, the 

 highest peak of the district. . . . The beds are tilted northward at 

 an angle of 15°-20°. Remnants of strata of about the same degree of 

 consolidation appear on the south side of the El Paso Range and dip in 

 the same direction. This seems to indicate a tilting en mass of the 

 range and adjoining country. 



J. H. Smith 14 gave the name "Mojave Formation" to the 

 sediments in Red Rock Canon, basing the name on Fairbank's 

 description, which is quoted above, and erroneously referring 



is Notes on the geology of eastern California, Am. Geol., vol. 17, pp. 

 67 and 68, 1896. 



1* The Eocene of North America, Journ. of Geol., vol. 8, pp. 455 and 

 456, 1900. 



