4 CONTENTS. 
Geology—Continued. Page. 
Sedimentary formations—Continued. 
* Monterey shale, (middle Miocene)—Continued. 
Structure and thickness. 47 
Evidence of age.'. 47 
Metamorphism of the shale by combustion. 48 
Localities where the shale is at present burning. 48 
Typical occurrences of burnt shale. 49 
Depth to which alteration has extended. 49 
Lithologic character of burnt shale. 50 
Cause of the alteration^. 51 
Range in time of the phenomenon. 52 
Fernando formation (Miocene-Pliocene-Pleistocene). 52 
General statement. 52 
Lithologic character. 54 
Structure. 56 
Distribution. 57 
Evidence of age. 57 
Quaternary. 60 
General statement. 60 
Terrace deposits. 60 
General description. 60 
Lithologic character. 61 
Origin. 63 
Dune sand. 63 
Alluvium. 64 
Igneous rocks. 64 
General statement. 64 
Igneous rocks of pre-Monterey age.. 64 
Igneous rocks intruding the Monterey. 65 
Geologic history.,... 66 
Earliest periods. 66 
Eocene period... 66 
Lower Miocene period. 67 
Middle Miocene period. 67 
Late Tertiary and early Quaternary period. 69 
Main Quaternary period. 70 
Structure and conditions affecting the presence of oil. 71 
The anticlinal theory. 71 
Accumulation of oil in the Santa Maria district. 72 
Indications of oil. 74 
General structural considerations. 75 
Detailed discussion of structure. 75 
\ 
Region of the San Rafael Mountains. 76 
Areas of rocks older than the Monterey. 76 
Areas of Monterey and later formations. 76 
Folds.*.. 76 
Faults. 77 
Evidences of petroleum. 78 
Conclusions regarding future development. 79 
Region of Santa Ynez Mountains.80 
Area south of Lompoc. 80 
Area of Santa Rita Hills. 80 
Main portion of the Santa Ynez Range. 81 
