186 CORALS AND CORAL ISLANDS. 
Group, the shore platform is seldom as extensive as at the 
Paumotus. It rarely exceeds fifty yards in width, and is cut 
up by passages often reaching almost to the beach. In some 
places the platform is broken into islets. Enderbury’s Island 
is one of the number to which this description applies. The 
beach is eleven or twelve feet high. or the first eight feet it 
slopes very regularly at an angle of thirty to thirty-five degrees, 
and consists of sand, coarse pebbles, or rounded stones of coral, 
with some shells; and there is the usual beach conglomerate 
near the water’s edge. After this first slope, it is horizontal 
for eighty to two hundred feet, and then there is a gradual 
rise of three to four feet. Over this portion there are large 
slabs of the beach conglomerate, along with masses from the 
reef-rock, and some thick plates of a huge foliaceous Madre- 
pora; and these slabs, many of which are six feet square, lie 
inclining quite regularly against one another, as if they had 
been taken up and laid there by hand. They incline in the 
same direction with the slope of the beach. The large Madre- 
pora alluded to has the mode of growth of the Madrepora 
palmata ; and probably the entire zodphyte extended over 
an area twelve or fifteen feet in diameter. The fragments 
are three to four inches thick, and thirty square feet in surface. 
As a key to the explanation of the peculiarities here ob- 
served, it may be remarked that the tides in the Paumotus are 
two to three feet, and about Enderby’s Island five to six feet 
in height. 
Maldive Archipelago.—The Maldives have been often 
appealed to in illustration of coral structures. They are par- 
ticularly described by Mr. Darwin from information commu- 
nicated to him by Captain Moresby, and from the charts of this 
officer and Lieutenant Powell. A paper onthe northern Mal- 
dives, by Captain Moresby, is contained in the Journal of the 
