THE BAHAMA ISLANDS. 213 



tales' Plateau is a true coral-rag, in other words, ordinaiy cor- 

 al reef-rock, — being made up of an agglomeration of fragments 

 of corals and sand, cemented into a solid limestone. 



^Bahama Islands. — The Bahamas (the western margin of 

 which is shown on the map of the Florida Reefs), are coral 

 reefs and reef islands, essentially like atoll reefs. The northern 

 end of the group lies opposite southern Florida, and from this 

 point they stretch off to the west of southwest in a double se- 

 ries, nearly parallel to the trend of Cuba and San Domingo, 

 and terminate properly in Turk's Island and some other 

 reefs north of the latter, — the whole length above 600 miles. 

 The 100-fathom line of soundings extends around the 

 two northern ranges of reefs and islands, which, therefore, 

 make up one bank, the Little Bahama Bank ; and another 

 similar line embraces the next six islands as parts of a 

 second Bank, called the Great Bahama Bank ; whose whole 

 length is about 300 miles. New Providence Island, the site 

 of the seat of government of the Group, Nassau, is the middle 

 one of the three northern islands of this Bank. The relation 

 of the eastern and western ranges of land in this Great 

 Bank is really analogous to that of the opposite sides of the 

 great Maldive Atoll Group. The remaining islands and reefs 

 are mostly isolated. In the triangular interval between the 

 Great Bahama Bank, Florida and Cuba, lies the reef called 

 Salt Key Bank. The northern coast of Cuba, south of this 

 Bank, and to the eastward, is bordered by coral reefs. 



Prof. Agassiz gives the following account of a part of 

 these reefs in the first volume of the " Bulletin of the Mu- 

 seum of Comparative Zoology." 



" The Bahamas and the reefs to the northeast of Cuba exhib- 

 it very abrupt slopes, and a great depth is reached close to the 

 shores of the Banks, so that the Bahamas resemble the coral 



