256 



EARTH FEATURES AND THEIR MEANING 



earthquake of 1899, although portions of the coast line were elevated 

 by as much as forty-seven feet, neighboring sections were raised by 

 smaller amounts, and some small sections were sunk and so far 

 submerged that the salt water and the beach sand were washed 

 about the roots of forest trees. 



A region racked by heavy earthquakes, where the present con- 

 figuration of the ground speaks strongly for a movement of some- 

 what similar nature, but with average movement of elevation much 

 greater to the northward than in the opposite direction, is the ex- 

 tended coast line of Chili. This country is characterized by a 

 great central north and south valley which separates the coast 

 range from the high chain of the Cordilleras to the eastward. To 

 the southward the floor of this valley descends, and has its con- 

 tinuance in the Gulf of Corcovado behind the island of Chiloe and 

 the Chonos archipelago. The known recent uplift of the coast of 

 Chili, particularly in the northern sections and during the earth- 

 quakes of the eighteenth, nineteenth, and twentieth centuries, 

 lends great interest to this topographic peculiarity. Indications 

 are not lacking that, during the earthquake of Concepcion in 

 1835, and of Valparaiso in 1907, the measure of uplift was greater 

 to the north than it was to the south. 



The contrasted islands of San Clemente and Santa Catalina. 

 Perhaps the most striking example of simultaneous opposite move- 



FIG. 287. Map of San Clemente Island, California, showing the characteristic 

 topography of recent uplift (after U. S. Coast and Geodetic Survey). 



ments observable in neighboring portions of the earth's crust 

 is furnished by the coast of southern California. The coast itself 

 at San Pedro and the island of San Clemente, some fifty miles off 

 this point, in common with most portions of the neighboring coast 

 land, have been rising in interrupted movements from the sea, and 

 offer in rare perfection the characteristic coast terraces (Fig. 287 



