30 BULLETIN: MUSEUM OF COMPAKAT1VE ZOOLOGY. 



again, and going south we soon pass into regions thickly covered with 

 the same underbrush which is so characteristic of the shores of all the 

 Bahama Islands ; and inland we get patches of aloes, of palmettos, and 

 of the forest trees characteristic of the Bahamas. 



The arch of the Glass Window was evidently foi'med by the undermin- 

 ing action of the sea, which little by little disintegrated the underlying 

 rock ; finally the overlying arch gave way in part, leaving an opening 

 known as the Glass Window, and remnants of the rocks forming the 

 arch lining the western sides of the opening. 



THE GLASS WINDOW. 



Both the northeast and northwest winds act upon the southern shores 

 of Northern Eleuthera, and are gradually eating away the outer shore 

 shelf, forming low vertical cliffs, and leaving here and there numerous 

 isolated rocks in from two to three feet of water, more or less water 

 worn, and eroded or diminutive islets formed by the general subsidence 

 and by erosion, which will gradually disappear and finally leave only the 

 uniform flat level of the parts of the bank adjacent to the islands. An 

 examination of the large-scaled charts of the Bahamas will show a large 

 number of such islets and islands anywhere in this group, either on the 

 windward or lee faces of the larger islands (see Plates IX., XII.). These 

 different islets are now prominent, according to the height of the original 

 hills of which they once made a part, or form shallow portions of the 

 principal banks. The long island to the south of Savannah Sound, on 

 the east face of Eleuthera, is an excellent example of such sloughing off 

 (Plate X. Fig. 2). 



The west face of Northern Eleuthera, as seen from our anchorage off 



