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APPENDIX II. 
tide-level is carried over the narrow reef to the lagoon by 
the waves whose throw on all sides is shoreward ; (3) lose 
in irregularity of outline and thus approximate towards an 
annular form ; (4) lose the channels through the reef into 
the lagoon by the growth of corals and by consolidating 
debris ; and (5) become at last a small bank of reef-rock 
with a half- obliterated lagoon basin. 
‘ The Pacific contains reefs of the three kinds : (1) atolls 
wfith much of the reef overgrown by trees and shrubbery ; 
(2) others, of large and small size, with the reefs mostly or 
wholly tide-washed ; (3) others, only two or three square 
miles in area without lagoons. Further, the different kinds 
are generally grouped separately and gradationally : (1) 
the islands of the Paumotu and Gilbert Archipelagos have 
usually half or more of the reef dry and green ; (2) the 
northern Carolines and the northern Marshall Islands and 
the eastern Feejees, although in fact of large size, are 
mostly bare reefs ; while (3) the islands of the Phoenix 
Group, of the equatorial Pacific east of the line of 180°, 
are, with one exception (Canton or Mary), not over four 
miles long. The three more southern of the Phoenix 
Islands, Gardner’s, Hull’s and Sydney, between 4° 25' S. 
and 4° 35' S., are two to four miles long and have lagoons ; 
five (islands), including Phoenix, Birnie’s and Kean’s be* 
tween 3° 10' S. and 3° 30' S., and Howland and Baker’s, 
north of the equator, are a mile and a half, and less, in 
length, and have depressions at the centre but no lagoons. 
The depressions contain guano, and one of them, Kean’s, 
has much gypsum mixed with the guano ; Kean’s and 
Phoenix have a foot or two of water at high tide, the tide 
rising six feet. Another of the number, Enderbury’s, is 
three miles long, and has a half-dried lagoon which is 
very shallow and has no growing corals. To the north 
of these islands for fifteen degrees of latitude, the sea is 
an open one, and in the next ten degrees, to the line of 
