ANALYSIS OF THE SOUNDINGS TAKEN BY THE "AMRA." 23 



(No. 37), with the same sort of bottom as nearer Kolumadulu. Within a 

 mile and a half from Maimbudu (South Nilandu), we obtained two hun- 

 dred and two fathoms (No. 38), with a bottom of fine greenish coral sand 

 mixed with many Globigerinae. 



The bottom of the western Kudahuvadu Channel is oceanic in character, 

 not only in the centre, but also quite close to South Nilandu, Mulaku, and 

 Kolumadulu; while the bottom of eastern Kudahuvadu Channel (Nos. 17, 

 19) is hard and swept clean by currents. 



Line across the Veimandu Channel from Timarafuri Pass (Kolumadulu) 

 to Munafuri (Haddummati) (PI. 8 c, fig. 20). 



Two and a half miles off Timarafuri we were already in seven hundred 

 and thirty-eight fathoms (No. 20), with a bottom of coarse coral sand and 

 broken shells. Seven miles off the starting-point in the centre of the 

 channel, the depth had increased to eleven hundred and eighteen fathoms 

 (No. 21) ; the bottom was still made up of coarse coral sand, though some- 

 what finer than that of the previous sounding. Two miles west of Waduni 

 Pass we obtained eight hundred and forty-three fathoms (No. 22). Three 

 quarters miles off" Haddummati, we sounded in eight hundred and ninety- 

 seven fathoms (No. 23), with a bottom of a mixture of coarse and fine coral 

 sand with many Globigerinae. 



Kolumadulu forms a bar across the southern extremity of the central 

 basin of the Maldives, on the two sides of which to the north are arranged 

 the great Maldive atolls, while to the south, including Kolumadulu, the 

 Maldives form only a single line of atolls. 



These soundings are interesting as showing the very sudden drop in 

 depth off the plateaus on the two faces of the Veimandu Channel. They 

 also illustrate the gradual increase in depth of the channels separating the 

 single groups as we go south, and the greater isolation of these plateaus as 

 compared to the shallower channels which separate the higher plateaus of 

 the northern and of the parallel chains of groups of the Maldives. 



The depth of the centre of Veimandu Channel is as great as that in the 

 channel separating the northern Maldives from Minikoi (PI. 7), though in 

 one case the channel is only sixteen miles wide, while in the other the 



