Vol. 7, No. 6, pp. 1 17-142, pis. 8-10 Issued December 4, 1912 



UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF THE DEPARTMENT OF 



GEOLOGY 



PHYSIOGRAPHY AND STRUCTURE OF THE 

 WESTERN EL PASO RANGE AND THE 

 SOUTHERN SIERRA NEVADA 



BY 



CHAELES LAURENCE BAKER 



CONTENTS 



PAGE 



Introduction 118 



The Western El Paso Range = 119 



Previous Investigations 119 



Geography 119 



Sequence of Formations 121 



The Basement Complex of Metamorphic and Plutonic Rocks 121 



Metamorphic Quartzite-conglomerate and Quartz-schist in 



Red Rock Canon 121 



Intrusive Hornblende Diorite-porphyry 121 



Acidic Igneous Rocks 122 



The Superjacent Series of Sedimentary and Volcanic Rocks 123 



The Black Mountain Basalt Flow 126 



Alluvium 128 



Structure 129 



Historical Geology 132 



Geologic History of the Consolidated Rock Members 132 



Geologic History Posterior to the Time of the Deposition of the 

 Rosamond Series as Inferred from the Structure and 



Physiography 134 



The Two Epochs of Post-Miocene Uplift with the Interven- 

 ing First Cycle of Post-Miocene Erosion 134 



Origin of Red Rock Canon and Last Chance Gulch 134 



Recent Faulting 136 



The Southern Sierra Nevada 137 



The Ricardo Erosion Surface 137 



Latest Epoch of Faulting, not Affecting the Entire Southern Sierra 



Front 139 



Dissection of the Sierra Debris Slopes 141 



Summary 142 



