ANALYSIS OF THE SOUNDINGS TAKEN BY THE "AMKA." 17 



Line from North Male to Gaha Faro (PI. 8 a, fig. 6). 



In the centre of the channel, between Gaha Faro and North Male, we 

 obtained a depth of one hundred fathoms (No. 48). The claspers only 

 brought up a fragment of pumice, covered with Bryozoa, Algae, and 

 Nullipores. 



Mr. Gardiner states that pumice was found on all beaches of the Mal- 

 dives, and that it was not known before the eruption of Krakatoa in 1883. 

 But pumice must have found its way on the beaches of the Maldives 

 earlier, as it occurs inland on many of the islands. 



The bottom of all the channels separating the composite atolls of the 

 central Maldives appears to be quite flat, the soundings off shore drop 

 rapidly ; generally at a distance of a mile and a half from either face they 

 attain a depth but little inferior to the greatest depths in the centre 

 of the channels. 



Line of soundings west of North Male (PI. 8 c, fig. 24). 



One mile due west, off the normal to the pass west of Hembadu, in the 

 centre of the western face of North Male, we obtained one hundred and 

 twenty fathoms, with coral sand (PI. 1). At a distance of three and one-half 

 miles the depth only increased to one hundred and fifty-nine fathoms with 

 a bottom of sticky coral sand, and at seven and one-half miles we ran only 

 into one hundred and eighty-six fathoms, with a bottom of fine green sand 

 filled with Globigerinae. 



Judging from this line of soundings and from the sounding's existing ' 

 between the northern part of Ari and Rasdu and Toddu, as well as to the 

 westward of these atolls, these atolls are on the western edge of a shallow 

 plateau extending west of North Male and north to Goifurfehendu. This 

 plateau separates the northern part of the central basin from the southern ; 

 it drops off very rapidly to the westward of Ari, if we may judge from the 

 line of soundings we ran to the west of the pass south of Mandu (Ari) 

 (PL 8 <?, fig. 2o). At a distance of three miles off the normal we ran into 

 nine hundred and eight fathoms (No. 8), and eight miles off Mandu Pass we 

 obtained fourteen hundred and ninety-eight fathoms (No. 9). The bottom 



1 Admiralty Chart, 6G a. 

 2 



