CONTENTS. 
Page. 
Introduction. 9 
Purpose of this report. 9 
Acknowledgments. 10 
Previous knowledge of the geology. 10 
Early history of the district.. 11 
Geography and topography. 15 
Location. 15 
Definitions of place names. 15 
Relief. 16 
General statement. 16 
San Rafael Mountains. IT 
Santa Ynez Mountains. 18 
Santa Maria Valley. 19 
Casmalia Hills. 19 
Solomon Hills. 20 
Los Alamos Valley. 21 
Purisima Hills. 21 
Burton Mesa. 22' 
Santa Ynez Valley and Santa Rita Hills. 23 
Terraced coast. 23 
General topographic features..’. 24 
Drainage and rainfall. 25 
Climate and vegetation. 26 
Geology. 26 
Sedimentary formations. 26 
General statement. 26 
Franciscan formation (Jurassic). 27 
Knoxville formation (lower Cretaceous). 28 
Pre-Monterey rocks. 28 
Tejon, Sespe, and Vaqueros formations, undifferentiated (Eocene- 
Miocene). j .. 29 
General statement. 29 
Lithologic character. 30 
Structure and thickness. 31 
Age and fossils. 31 
Monterey shale (middle Miocene). 33 
General statement.,. 33 
Lower division. 34 
Upper division. 36 
Diatomaceous earth deposits. 38 
Composition of the Monterey shale. 39 
Material of shale. 39 
Microscopic appearance. 43 
Chemical composition. 44 
Alteration. 45 
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