ANA: CORALS AND CORAL ISLANDS. 
ridge of rounded knolls, not unlike ‘roches moutonnées,’ at 
intervals interrupted by breaks, so that the whole looks like a 
dismantled wall, broken down here and there to the water’s 
edge. The whole ridge is composed of the finest odlite, pretty 
regularly stratified, but here and there like torrential depos- 
its; the stratification is more distinctly visible where the rocks 
‘have been weathered at the surface into those rugged and 
furrowed slopes familiarly known as ‘ karren’ in Switzerland. 
\ It is plain that we have here the same formation as on Salt 
Key, only older, with more thoroughly cemented materials.” 
The Bahama Islands. —The Bahamas are, like the Flor- 
ida reefs, great coral-made banks, having their emerged land 
in the form of islands and cays. These dry portions are 
situated mostly along the windward sides. To comprehend 
the relations of the Bahamas to atolls they should be com- 
pared with the Louisiade Group, Plate VII., and other broad 
combinations of barriers and atolls, although true barrier 
reefs are absent. They are more remarkable than the Flor- 
ida reefs for their drift-sand accumulations, their height be- 
ing sometimes two hundred to two hundred and thirty feet, 
though generally under one hundred feet. A large part of 
the banks, however, are in a lagoon condition, being covered 
with water at depths ordinarily of two to five fathoms, and 
the leeward margin is for the most part submerged. 
The group extends for six hundred miles through the seas 
north of Cuba and Hayti, with the Florida Straits — fifty miles 
in mean width and three to five hundred fathoms in depth — 
separating them from Florida. The two great western banks 
are the Little Bahama, or the northwestern, one hundred and 
fifty miles long, and the Great Bahama Bank, to the south 
and east, three hundred and twenty-five miles long. The 
latter is shaped like a letter 8, or a pothook, and occupies two 
