THE 
(Om NA OF GCEOLOGY 
SE PME NVBER OCHOBIR TS98 
GEOLOGY OF A PORTION OF THE SOUTHERN 
COASDPAIRANGES= 
CONTENTS. 
Introduction. “ 
Topographical features. 
Sedimentary terranes. 
Jurassic period. 
Golden Gate series. 
Cretaceous period. 
Knoxville beds. 
Chico formation. 
Tertiary period. 
Neocene. 
Monterey series (Lower Neocene). 
San Pablo formation (Middle Neocene). 
Paso Robles formation (Upper Neocene). 
Pleistocene. 
Igneous rocks. 
Structural geology. 
Geological history. 
INTRODUCTION. 
Ir is the intention to present in the following paper a résumé 
of the most important results obtained during a detailed study 
of a portion of the southern Coast Ranges of California. 
The area embraces about 570 square miles in the western 
part of San Luis Obispo county with the town of the same 
name nearly in the center. It has a length from north to south 
of thirty-five miles and an extreme width from east to west of 
* Published by permission of the director of the United States Geological Survey. 
Vou. VI, No. 6. 551 
