118 THE SALTON SEA. 



hill which bore no seed-plants by reason of lack of soil and rose 40 or 50 feet above the water. 

 No landings were made on it. Obsidian island was of dumb-bell shape nearly a mile in 

 its main axis, which lay nearly north and south. The shores of the bays on the eastern and 

 western sides were of sand and alkaline clays and this formation extended southward on 

 the eastern side. These conditions, together with the fact that the island lay in the drift 

 from the Alamo inflow, cooperated to yield some very interesting features. Cormorant 

 Island, 2 miles to the northward, was awash during the period of maximum depth of the 

 lake and was completely sterilized. It is to be noted that the names given to these islands 

 were applied solely for the convenience of the workers of the Desert Laboratory and as 

 they were not formally published have not been generally recognized. Other names for 

 the same formations have probably been used by visitors to the lake, but so far as the 

 author is aware none have been formally presented, and as a matter of course the sub- 

 sidence of the lake will restore the elevations to their status as hills, which may or may 

 not have received definite appellations (Plate 16 b). 



The islands bore a sparse vegetation, including four species of Atriplex. Lizards and 

 small rodents were found on Big Island and Obsidian Island. A coyote had survived for 

 a short time on Obsidian Island. The amount of food on Big Island was such that in Feb- 

 ruary 1907, a year or more after this elevation had been surrounded by water, rabbits 

 and a raccoon were still alive, as indicated by their tracks and burrows. The isolation 

 of the tops of these arid hills as islands by the waters of the lake made them attractive to 

 aquatic birds, and Obsidian Island became the site of an extensive nesting-place for pelicans 

 as early as 1907, while some cormorants made nests here and also on the top of the smaller 

 island to the northward, which was barely awash at high water and was named Cormorant 

 Island. Representatives of the fishes of the Colorado River had come into the Sea, but 

 did not seem to multiply, with the exception of the introduced carp, which afforded a food 

 supply of some importance to these birds. Nothing definite may be said about the move- 

 ments of other flying species, but it is well known that those mentioned above make long 

 flights southward through the Delta to the Gulf of California and along the course of the 

 Colorado. The possibility of seed-introduction by these birds awakened the liveliest inter- 

 est, although it was probable that the plants which might thus be carried to the islands 

 were likewise the ones which might be most readily borne there by flotation. In any 

 analysis of possible introductions, therefore, the positions of the established plants with 

 regard to the water-level would need careful consideration. 



LAGUNA MAQUATA. 

 After a brief survey of the lake an excursion two weeks in length was made to another 

 sunken basin to the southward, which lies to the westward of the Cocopah Mountains in 

 Baja California, a province of the Republic of Mexico. The Sink of this basin had been 

 seen to be receiving an inflow from the Colorado River around the southern end of the 

 mountains in April 1905, but nothing was known as to how long this continued. It may 

 be assumed, however, that it ceased with the passing of the summer flood of the Colorado 

 in June of that year, since the water in March 1907 was 12 to 15 feet below the maximum 

 level, which loss or recession could be attributed chiefly to evaporation, which for adjacent 

 regions has been calculated as over 100 inches per year. The body of water formed here 

 has been variously known as the Laguna Salada and Laguna Maquata. The lake was 

 known to be in existence in 1884, was represented by a chain of saline pools in 1890 was 

 seen in much the same condition in 1892, and filled again in 1893. Exact records of the 

 cycle of the lake are not available, but it is known to have become entirely dry at various 

 times up to 1905, when it was seen to be filling as noted above. The rate of evaporation 

 would probably result m the desiccation of the lake in 1909, but early in April 1910 it was 

 again reported to be filling in connection with serious disturbances in the lower course of 



