UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF THE DEPARTMENT OF 



GEOLOGY 



Vol. 8, No. 19, pp. 335-363, pis. 32-38 Issued December 31, 1914 



TERTIARY MAMMAL BEDS OF STEWART AND 

 IONE VALLEYS IN WEST-CENTRAL NEVADA 



BY 



JOHN P. BUWALDA 



CONTENTS 



PAGE 



Introduction 335 



Geographic Features of the Region 336 



Geology of the Region 338 



Cedar Mountain 338 



Limestones 338 



Granular Intrusives 340 



Lavas : 340 



Stewart and lone Valleys 341 



Underlying Rocks 341 



Esmeralda Formation 342 



Distribution 343 



Lithology 344 



Thickness _ 347 



Stratigraphic Relations 348 



Structure 348 



Fauna, .Age, and Correlation 350 



Fanglomerate Mantle 352 



Southern Gabbs Valley Range 353 



Physiographic History 355 



Physical Conditions During Upper Miocene Time 359 



Geologic History of the Region 361 



INTRODUCTION 

 The following paper is based upon observations made by Mr. 

 Charles Laurence Baker and the writer in the course of a brief exam- 

 ination of the region about Cedar Mountain, Mineral County, west- 

 central Nevada, during parts of May and June, 1912, and upon facts 

 gathered by the writer during a reconnaissance, in June, 1914, south- 



