The Great Valley 



133 



Range or western side dipping toward the east and north. The 

 axis of the Great Valley is thus the line of greatest depression, 

 or the bottom of the trough. The broader side of the trough 

 or valley floor is on the Sierra side, the uplift of the great Sierra 

 Range carrying with it the wider portion about two-thirds 

 of the basin floor. The bottom or floor of the basin is not uni- 



Phofo by Hitt. Courtesy Tracy Chamber of Commerce 



FIG. 38. Dairy herds in San Joaquin County, in the heart of the Great 

 Central Valley. 



form, but has been disturbed by upheavals that reached out 

 from the mountain ranges. In some cases upheavals branching 

 out from the adjacent mountain ranges resulted in humps or 

 anticlines. Such anticlines are the "structures" which have 

 determined the great petroleum oil fields. Such anticlinal 

 folds in the rocks are the Coalinga anticline, Antelope Hills, 

 the groups of anticlines in the Elk Hills and the Buena Vista 



