262 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13 



able to erode the soil excessively. The roots of trees and shrubs have 

 been exposed and the plants eventually killed. On San Miguel many 

 of the ancient kitchen middens of the aborigines are now^ perched on 

 ridges fifteen to twenty feet above the surrounding level. The surface 

 covering of shell, bone, and rock fragments has slowed the erosion of 

 the middens themselves. The airplane vievi^ of San Miguel Island, 

 plate 2, taken prior to 1933, shows the results of wind erosion. The 

 direction of the prevailing winds is indicated by the deep, parallel 

 trenches eroded in the sandstone. At the time of the writer's visit to 

 the island in 1940 vegetation had already started to reclaim some of the 

 waste land in the east and west parts of the island. This was made 

 possible by the fact that, for several years, the number of sheep had been 

 limited to three thousand. 



San Nicolas is nearly as windy as San Miguel. It has been grazed 

 continuously for about seventy-five years. Hence, as a result, the island 

 has undergone great wind and water erosion. When George Nidiver 

 removed an Indian woman from San Nicolas in 1853 he found Lava- 

 tera assurgentiflora (malva real) bushes and '*a species of moss,, grow- 

 ing about the hut of the Indian woman (Ellison, 1937). Today the area 

 about the hut and, indeed, that entire end of the island is a desolate 

 waste of wind-driven sand. The steep slopes leading to the central mesa 

 have been cut into a ''bad lands" by water erosion and the gullies are 

 rapidly eroding back into the upland. 



While Santa Rosa is somewhat less windy than either San Miguel 

 or San Nicolas, many areas are badly wind-eroded. However, grazing 

 here has been under careful management since 1893. The rule has been 

 to stock the island only to the extent for which the forage of the driest 

 year will be amply sufficient, and to rotate the pasturage so that it is 

 only grazed once in three years. Nevertheless even this plan failed for 

 the cattle had to be removed from the island during the dry seasons 

 of 1946-1948. Water erosion has been the principal erosion problem on 

 Santa Cruz, but check dams and contour cultivation indicate careful 

 conservation of the arable areas by the Caire family during their long 

 ownership of the island. 



The effects of wind erosion have greatly increased the sand dune 

 areas on San Nicolas, San Miguel, Santa Rosa, and San Clemente. It 

 is probable that only small coastal dunes were present originally, and 

 the larger dune areas of the present were originally occupied by the 

 forbs and semi-shrubs reported by early travelers. There is no evidence 

 to show that the small salt or fresh-water lagoons on most of the islands 

 have been materially changed since earlier times, except as the result 

 of natural succession. 



