336 



Adventures in Scenery 



and extended farther west than now. The Peninsular Range is 

 a vast block of the earth's crust that was uplifted, broken by 

 faults on the east, and rotated, that is, lifted more on the east 

 and less on the west. The coastal plain, extending 8 to 12 miles 

 to the east from the ocean, was in comparatively recent time 

 geologically (Quaternary) depressed so that it was covered by 

 the sea. Just how far what is now the Peninsular Range was 

 affected by these earth movements is not known, but the coastal 



Photo by A. J. Ellis, U. S. Geol. Survey 



FIG. 102. Wave-worn pebbles, Encinitas. (A fine beach is at Ocean- 

 side.) Pebbles carried in seaweeds by tides. 



belt was depressed below sea level. This is now the belt of flat, 

 high upland benches or terraces, popularly called the mesas. 

 Linda Vista mesa, to the north, stands 400 to 500 feet above sea 

 level. Terraces range in height from 20 feet to 1200 feet above 

 sea level, but range generally from 300 to 500 feet. 



Mounds or hummocks on Linda Vista mesa have attracted 

 much attention, and may be observed from the highway. 

 They are thought to be wind-formed, the product of desert 



