200 E. B. Hunt on the Florida Reef. 
violent, and they are constantly giving way before the assaults of 
the waves and the corrosions of the numerous and active boring 
shells. A coral mass once broken loose undergoes active att 
tion and disintegration into calcareous sand of varying fineness. 
This sand, and the accompanying detritus of shells and echino- 
derms, which abound intermixed with the living coral, are 
egrees borne on by the waves towards the south beaches of the 
keys, where some of the sand is thrown up on the slope of the 
beach ridge. A coral mass or shell once cast loose is killed, and 
is henceforth untiringly triturated by the waves, until it escapes 
their action, or is reduced to impalpable powder. Every agita- 
tion of the sand by the waves pulverizes it yet further, and 
brings it nearer to the consistency of the white mud which so 
largely prevails on the Bank towards its northern side. There 
is thus constant coral and shell growth and as constant disinte- 
gration in progress. | this action however takes place in the 
limited range of depth of less than 100 feet, within which only 
ean the reef building corals grow. To account for the vast un- 
derlying mass, between this limit of depth and the deep original 
sea floor, is a problem hitherto unsolved and one which I hope 
to.elucidate. 
e tidal currents set strongly across the reef and through 
the channels between the keys, the flood running to the north 
and the ebb to the south side of the key crescent. When storms 
occur, the agitation of the waves extends to the bottom, over the 
shallower portions of the grand Bank, and stirs up the sand v10- 
lently. This causes the water to take up and maintain in me 
chanical suspension such finely comminuted particles as pes 
whole Bank. This ‘white water” is a familiar appearance, and 
is one of the sure signs of proximity to the reef. As storms 
subside, the white sand and mud are gradually thrown dow? 
and the water clears, after a day or two, to its peculiarly delicate 
transparency. | 
During the “ white water” periods, the flood tidal currents set 
the white water over the north side of the Bank into the Bay 
of Florida, where, by reason of the greater depth, the process © 
deposition goes on; and thus the floor of this bay has becom? 
