SANTA MARIA TO LOS ARROYOS 131 



The presence of the Gulf Stream, which im- 

 pinges upon the reefs, together with the high tem- 

 perature of the water within the outer barrier 

 (82 to 84 in May and June), would justify belief 

 that a great wealth of marine life must here exist. 

 Our expectations in this respect were not fully 

 realized, a lack of diversity of bottom conditions 

 probably accounting for it. It is hardly correct to 

 speak of a paucity of life within the area described, 

 but better of a lack of diversity of animal groups 

 that a wider range of stations would certainly 

 provide. Throughout the entire length of this 

 section of coast, there is no trace of shore lime- 

 stone; none of the Tertiary beds of the east, nor 

 of the elevated Pleistocene reefs of Cape San 

 Antonio. 



About noon, while proceeding toward Arroyos, 

 we sighted, just off our course, a large sand flat 

 with about a half-acre exposed. We dropped 

 anchor fifty yards from the little island and all 

 put ashore with collecting equipment. This sand 

 flat presented an exceptionally fine opportunity 

 for study of such character of station, and we made 

 a very thorough exploration of it. Owing to the 

 shifting nature of the sands the flats seemed to be 



