472 IN als JDVZURTNOUN] 
Fig. 1, in which are also indicated the nearest occurrences of Cambrian 
rocks previously known. At GW is the Grand Wash escarpment on 
the western margin of the Arizona plateau traversed by the Grand 
Canyon of the Colorado. In this escarpment is the well-known suc- 
cession of 1,000 feet or more of the Tonto (Middle Cambrian) sand- 
stones and shales lying on pre-Cambrian granites and overlain by 
several thousand feet of Carboniferous limestones. 
Cambrian rocks have been described by J. E. Spurr? on several 
ranges in the southern portion of Inyo County, extending to and 
slightly over the northern margin of San Bernardino County. These 
descriptions were based partly on his own observations and partly on 
notes of a trip made by Mr. R. B. Rowe. The most extensive areas 
which are in and near the Kingston Range (K, Fig. 1) were discovered 
by Mr. Rowe. ‘The rocks here consist of over 1,500 feet of quartzites 
of various colors and limestone, sandstones, and shales. One mass 
of massive dark-blue limestone is mentioned. The rocks contain 
fossils at different horizons, some of which are stated to be lower 
Cambrian. They lie on gneisses and other crystalline rocks. In the 
southern end of the Funeral Range (F. in Fig. 1) there are about 
2,000 feet of slates, limestones, conglomerates, and quartzites noted 
by Gilbert? and Campbell. These observers found no fossils and 
Campbell suggests that the rocks may be of pre-Cambrian age. Mr. 
Spurr maps them as probable Cambrian. Some of the beds in Slate 
Range (see Fig. 1) and west of Randsburg are mapped as Cambrian 
by Spurr on the authority of H. N. Fairbanks,+ who refers to them as 
“probably Paleozoic.” 
In the White Mountain Range, over too miles north, there are 
nearly 5,000 feet of sandstones, shales, quartzites, and limestones, in 
which Mr. Walcott’ discovered an extensive series of Lower Cambrian 
fossils. In certain parts of the range the rocks are cut by great masses 
of intrusive granite. 
In the Spring Mountain and Las Vegas regions, southern Nevada, 
tU. S. Geological Survey, Bulletin No. 208 (Washington, 1903). 
2U. S. Geographical Survey West of the tooth Meridian, Vol. III, p. 170. 
3 U. S. Geological Survey, Bulletin No. 200, p. 14 (Washington, 1902). 
4 American Geologist, Vol. XVII, pp. 65, 149. 
5 American Journal of Science, Third Series, Vol. XLIX (1895), pp. 141-44. 
