AGASSIZ: BAHAMAS. 



53 



vertical cliffs of about eighteeu inches in height, presenting all the 

 appearances of water action so characteristic of the higher limestone 

 cliffs on other islands of the Bahamas. The diminutive seas had eaten 

 out small bays, formed promontories, and indented the coast in a man- 



YOUXG MANGROVES, WIDE OPENING. 



ner no less characteristic than the shore lines of higher islands when 

 exposed to the full action of the trades. Masses of dead shells are found 

 blown up or thrown up on the diminutive beaches of the recesses cut out. of 

 the shore line. Billy and Williams Islands must at one time have formed 

 a part of the northwestern extension of Andros. There is no part of the 

 Bahama Bank which is so instructive as that now occupied by Andros. 

 Nowhere else do we find so large an island undergoing all the pi-ocesses 

 of disintegration, division, and erosion which have on other parts of the 

 bank ended in forming the submarine shoals, and leaving here and there 

 traces of the former extension of the larger islands of which the bank 

 was composed. Andros still occupies a comparatively large part of the 

 Great Bahama Bank to the west of the Tongue of the Ocean ; yet it is 

 cut into three islands by the so called bights which connect the Tongue 

 of the Ocean with the shallow waters of the bank to the westward of 

 Andros. Its former southern extension is marked by the numerous 

 small islands, isolated rocks, sand banks, and ridges reaching southward 

 and eastward from the southern end of Andros. Its former western 



