Ch. V. OF CORAL-REEFS. 121 



Archipelago in which the islands are numerous— the 

 plan always adopted — the figure will be a pointed 

 ellipse (reaching from Hood to Lazaref Island), of 

 which the longer axis is 840 geographical miles, and 

 the shorter 420 miles : in this space, 1 none of the 

 innumerable islets, united into great rings, rise above 

 the stated level. The Gilbert group is very narrow, 

 and 300 miles in length. In a prolonged line from 

 this group, at the distance of 240 miles, is the 

 Marshall archipelago, the figure of which is an 

 irregular square, one end being broader than the 

 other ; its length is 520 miles with an average width 

 of 240 : these two groups together are 1 ,040 miles in 

 length, and all their islets are low. Between the 

 southern end of the Gilbert and the northern end of 

 Low Archipelago, the ocean is thinly strewed with 

 islands, all of which, as far as I have been able to 

 ascertain, are low : so that from nearly the southern 

 end of the Low Archipelago to the northern end of 

 the Marshall Archipelago, there is a narrow band of 

 ocean more than 4,000 miles in length, containing a 

 vast number of islands, all of which are low. In the 

 Western part of the Caroline Archipelago, there is a 

 space of 480 miles in length, and about 100 in breadth, 



1 Metia or Aurora Island has been upraised ; but it lies N.E. of 

 Tahiti, and in the map appended to this volume is close without 

 the line bounding the space here referred to. I shall have occasion 

 hereafter to make some remarks on the supposed slight elevation (of 

 about three feet) of the atolls of the Low Archipelago, subsequently to 

 their original formation. 



