PART FOUR 



THE SCIENTIFIC BACKGROUND 

 THE STRUCTURE. 



The geologic structure — especially the faulting — 

 has been of tremendous importance in creating, out- 

 lining and defining the physiographic features of the 

 country in its relations to climate, to distribution 

 of water below and above ground, to the soils, to the oc- 

 currence of oil fields, to seismicity and to human en- 

 vironment in general. Without a knowledge of the oc- 

 currence and extent of the great master folds and 

 faults of Southern California no one can have an un- 

 derstanding of the fundamental conditions that answer 

 and explain the question "Why is Southern Cali- 

 fornia?"^ 



Aside from the materials which enter into the mak- 

 ing of a house, the ultimate aspects of the building 

 will depend upon how these materials are arranged or 

 put together to make the completed edifice. 



The arrangement of the materials in the building of 

 the earth, as well as of houses, is technically known 

 as "structure." This includes the position and atti- 

 tudes of the rock units relative to one another, such 



'Prior to the recent successful utilization of geol<JKy in the matter of oil 

 exploration, mere mention of the word producetl an unfavorable mental reac- 

 tion upon the average man, who associated it with things of but little human 

 interest, such as vague pre-nebula hypotheses, dreary eons of Paleozoic time, 

 dark, slimy seabottoms, with remains of millions of once creeping things, 

 no longer living, with names as far from understandable English as possible. 



