428 



SCIENCE. 



[N. S. Vol. XVIII. No. 457. 



Dr. W. C. Coker, of the University of North 

 Carolina, chief of the botanical staflf. 



Messrs. C. A. Shore and F. M. Haynes, of the 

 University of North Carolina, botanical assist- 

 ants. 



Mr. Barton A. Bean, curator of fishes in the 

 United States National Museum, chief of staff 

 of marine zoology. 



Messrs. J. B. Custis and J. A. Lewis, of Johns 

 Hopkins, assistants in marine zoology. 



Mr. J. H. Kiley, curator in the United States 

 Museum, chief of staff for land zoology. 



Mr. S. H. Deriekson, assistant in land zoology. 



Dr. Oliver L. Fassig, section director of the 

 United States Weather Bureau, chief of staff of 

 climatology and physics. 



Mr. J. E. Ruth, Johns Hopkins University, 

 assistant in climatology and physics. 



Mr. C. N. Mooney, United States Department 

 of Agriculture, chief of the soil survej'. 



Messrs. J. C. Britton and E. C. Hughes, United 

 States Department of Agriculture, assistants in 

 soil survey. 



Mr. J. M. Wright, Johns Hopkins, historian. 



Mr. A. H. Baldwin, of Washington, artist. 



Mr. Frank Gilmore, foreign correspondent. 



The results of the expedition may be 

 briefly summarized as follows: 



GEOLOGICAL SURVEY. 



Work of Previous Investigators.— Many- 

 geologists have visited the Bahama Islands 

 in times past, have studied the geological 

 formations with more or less care and have 

 arrived at the following conclusions : 



1. The material of which the Bahama 

 Islands are built is wind-blown coral sand. 



2. The islands were formerly very much 

 more extensive than now. 



3. They are gradually being depressed 

 beneath the surface of the Atlantic Ocean. 



4. They are gradually being eroded by 

 the waves. 



5. They are slowly being elevated. 



It will be noticed that there are two op- 

 posing views here, namely, that the islands 

 are undergoing subsidence, and second, 

 that they are being elevated. 



Conclusions Arising from the Present 

 Survey.— The geology of the Bahama Isl- 



ands is not difficult or extremely varied. 

 It presents a number of most iutei-esting 

 problems and exhibits a number of most 

 instructive types of topography. The 

 present survey has been able to determine 

 that the material composing the Bahama 

 Islands is not entirely made up of wind- 

 blown coral and lime sand, but the lower 

 portions of many of the islands, extending 

 up to ten or fifteen or twenty-five feet 

 above the present level of mean tide, has 

 been deposited by the ocean and contains 

 marine organisms in large numbers. Above 

 this lies the deposit of wind-blown material 

 which has up to this time been regarded 

 as the sole type of deposit visible through- 

 out the archipelago. 



In regard to the question of elevation or 

 subsidence, the survey has determined that 

 both processes have taken place. The isl- 

 ands Avere doubtless much higher at one 

 time than to-day, and it is equally certain 

 that they were formerly more depressed 

 beneath the Atlantic Ocean than they are 

 now. It is impossible to say whether they 

 are being elevated or submerged at the 

 present time, as the process is extremely 

 slow at best, and can only be detected by 

 careful measurement extending over long 

 periods of time. It is for this reason and 

 to settle this question that a bench mark 

 and tide gauge have been erected at Nassau. 



BOTANICAL SURVEY. 



Previous Investigations on Plants.— A 

 number of botanists have made more or less 

 extensive investigations on the plants in 

 the Bahama Islands, but as a rule their 

 studies have tended toward purely system- 

 atic classification of the flowering plants 

 and published lists of the same with their 

 localities thi-oughout the archipelago. 



Present Botanical Survey.— The work of 

 the present survey has been : 



1. To supplement the systematic work 

 of earlier investigators by visiting islands 



