20 PHYSIOGRAPHY AND GEOLOGY 



history opened when the Islands were elevated about 15 or 20 feet to their 

 present position and brought up with them the marine deposits just mentioned. 

 It is not known whether the Islands at the present time are undergoing 

 subsidence or elevation or whether they are stationary. In order to establish 

 this point bench marks have been erected at Nassau which are described in 

 full in another part of this volume. It will be interesting for future geologists 

 to determine the position of these marks after a lapse of twentj^-five or fifty 

 years. 



