A. Agassiz — Expedition to the Maldives. 301 



increased to 649 fms. Returning now to the groups of the 

 western chain of atolls we found 231 fathoms in the Ariyaddu 

 Channel between Ari and JSTorth Nilandu. The charts indicate 

 200 fathoms in the center of the channel between North and 

 South Nilandu and between it and Kolumadulu, the northern- 

 most of the southern single chain of atolls, we found 251 fathoms 

 in the center of the channel. 



In the wider channels separating the atolls of the southern 

 single chain the depths become much greater. In the center 

 of the Yeimandu Channel which separates Kolumadulu and 

 Haddummati, the depth had increased to 1,118 fms., and 

 half way between it and Suvadiva we found a depth of 

 1,130 fms. In the wide channel between Suvadiva and Addu 

 we found 1,292 fms. a little to the north of Fua Mulaku and 

 1,048 fms. between it and Addu. At a distance of four and a 

 half miles to the south of Addu we ran into 718 fms. Owing 

 to the rough weather we were obliged to discontinue our 

 southern line, which I hoped to connect with the single sound- 

 ing of 2,500 fms. between Addu and Chagos indicated on the 

 Admiralty Charts. I believe that the " Yaldiva" also made a 

 few soundings between Ceylon and Suvadiva as well as south 

 of Addu on her way to Diego Garcia; unfortunately I have not 

 her list of soundings at hand, and am not able to state what 

 light they throw on the depths separating Addu, the southern- 

 most of the Maldives from the Chagos Archipelago. 



The bottom samples of the deeper soundings were interest- 

 ing as showing the existence of Globigerinae in great quanti- 

 ties at a comparatively short distance from the shallower parts 

 of the Maldive platean. Though we did not find Globigerinae 

 in our tows except on one occasion, G-lobigerinae were fre- 

 quently so abundant on the bottom as to form what might be 

 called Globigerinae sand. In somewhat shallower soundings 

 and nearer the atolls Pteropod shells were common, and these 

 we collected in numbers in nearly all our tows made on the 

 outer faces of the Archipelago. In two of the soundings in 

 the channels between the composite atolls we brought up small 

 manganese nodules existing much in the condition in which 

 they were dredged by the " Blake " in the Straits of Florida. 



As regards the slopes of the eastern and western faces of the 

 Maldive plateau our soundings are of considerable importance. 

 The soundings of Ihavandiffulu found on the charts indicate 

 a depth of over 1000 fms. off the southwestern face at a dis- 

 tance of nearly twelve miles. Off the northeastern face nearly 

 the same depth is reached in less than six miles. To the east 

 of the northernmost point of Tiladummati, at a distance of 

 seven miles, T81 fms. is indicated on the chart, and about 13 

 miles to the eastward we ran into 1,460 fms. In the center of 



