218 J. E. SPURR ORIGIN AND STRUCTURE OF THE BASIN RANGES 



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Toyabe range 230 



Walker River range 231 



Pinenut and Virginia ranges and the eastern face of the Sierras 231 



Excelsior range 232 



Resume of ranges of western central Nevada 233 



Ranges of southern Nevada 233 



Virgin range 233 



Mormon range 234 



Meadow Valley range 234 



Las Vegas range 235 



Spring Mountain range 235 



Pahroc, Hy ko, and Pahranagat ranges ' 236 



AVortliington mountain 238 



Resume of ranges of southern Nevada 238 



Ranges of California adjacent to soutiiern Nevada 238 



Wiiite Mountain range 238 



Grapevine and Funeral ranges 239 



Kingston range 239 



Mojave desert 240 



Colorado plateau 240 



General conclusions as to origin of Basin ranges of Nevada and California.... 241 



History of deformation in the Great Basin province 242 



Late Cambrian movement 242 



Post- Devonian movement 243 



Post-Carboniferous movement 243 



Post-Jurassic movement 243 



Post-Cretaceous movement .- 244 



Eocene movements 245 



Miocene movements 246 



Pliocene 246 



Pleistocene 247 



Conclusion 2-18 



Record of post-Mesozoic erosion in the Great basin 249 



Cretaceous erosion 249 



Tertiary-Pleistocene erosion.. 249 



Climatic control 249 



General leveling teiulency 251 



Active erosion in moister climatic intervals 251 



Erosion in drainage basins of Pleistocene lakes 251 



Erosion of southeastern Nevada dry valleys 252 



Description of valleys 252 



Age and origin of valleys 252 



Net result of leveling and differentiation tendencies 255 



Aridity as a promoter of steep slopes 255 



Relative ascendency of erosion and deformation 256 



Relative ascendency of folding and erosion 256 



The synclinal ridge of erosion 256 



The anticlinal ridge of erosion 256 



