34 
RECONNAISSANCE OF PART OF WESTERN ARIZONA. 
The material is similar in character to the travertine capping 
Greggs breccia (section C, fig. 4), and to that occurring in beds 500 
feet or more in thickness in the mouth of Grand Canyon (section A, 
fig. 3). It is apparently a travertine deposit belonging either to the 
Greggs deposits, let down to its present position by faulting (section 
D, fig. 4) or to the Temple Bar deposits, both of which are known to 
contain large beds of travertine. Its relation to the sedimentary 
rocks and to the 
underlying granite 
of the tilted block 
to the east is shown 
in the sketch sec- 
tions in fig. 4. 
Within the can- 
yon, resting uncon- 
formable upon Tem- 
ple Bar conglomer- 
ate and the older 
formations at vari- 
ous points on either 
side up to an alti- 
tude of 150 to 200 
feet above the water 
level, occur uncon- 
solidated gravels. 
They are not con- 
spicuous east of Ice- 
berg Canyon, al- 
though some gravel 
beds in the Grand Wash Trough above high-water level may have 
been formed at the same time. Farther downstream they are con- 
spicuously developed and are there known as the Chemehuevis gravel. 
VIRGIN CANYON. 
Fig. 4.— Diagrammatic sections across Colorado River. C, 4 miles 
east of Greggs Ferry ; D, near Hualpai Wash; E, in Virgin Canyon. 
1, Basalt; 2, Temple Barconglomerate; 3, Greggs breccia; 4, Redwall 
limestone; 5, Cambrian; 6, granite; 7, travertine. 
At the mouth of Hualpai Wash Colorado River enters a narrow 
rock gorge cut in the crystalline rocks of the Virgin Range. The 
canyon is about 5 miles long and from 1,000 to 1,500 feet deep, with 
walls rising steeply from the water's edge on either side. 
High in the sides of the canyon walls occur remnants of light- 
colored, horizontally bedded material. (See section E, fig. 4.) These 
were not examined closely, but from a distance they have the same 
general appearance as the Temple Bar conglomerate characteristically 
developed at the same altitude a few miles farther west. 
