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F. E. PEABODY AND J. M. SAVAGE 



Province of Nevada. The corridor is bordered on the west by the 

 ocean and on the east by a great structural depression, only re- 

 cently reclaimed from the sea by continental uplift. 



The data of geology (Taliaferro, 1943; Eardley, 1951) supply 

 antecedent chapters in the formation of the corridor. Geomor- 

 phologic provinces of California (Fig. 1) show that the site of the 

 present corridor was dominated by a large geosyncline receiving 

 mainly marine deposits in the approximate position of the Great 

 Valley of California during most of the Cenozoic. Adjacent struc- 

 tural basins of marine deposition to the south contributed to the 

 limiting of the stable edge of the continent to a line running length- 

 wise through the middle of modern California. The area of the 

 corridor was an archipelago at best during most of the Cenozoic. 



During the Miocene epoch the area of the future corridor was 

 essentially "wiped clean" of terrestrial organisms by maximum 

 flooding of marine waters (Fig. 2). Flooding was followed by ac- 

 celeration of orogeny in the Coast Range belt. The orogeny surged 

 to one peak in late Pliocene, affecting mainly the western part of 

 the Central Coast Ranges, and to a second peak in the Mid-Pleisto- 



UPPER MIOCENE 

 PALEOGEOGRAPHY 



r 



Fig. 2. Late Miocene paleogeography of California, showing extensive 

 marine flooding in position of present Central and Southern Coast 

 Ranges. (After Camp.) 



