2 ME. J. S. GAEDINEE ON THE GEOLOGY OF EOTUMA. [Peb. 1898. 



II. TOPOGEAPHY. 



The island of Eotuma is situated in lat. 12° 30' S. and long. 

 177° r E. ; it is thus about 260 miles almost due north of the 

 Tasawas, the nearest islands in the Fijian group. According to the 

 ChalUnger^s charts it lies in a general depth of 2000 fathoms, on a 

 plateau which includes the Pijian, Tongan, Samoan, and Ellice 

 Islands. The soundings of H.M.S. Penguin : 2438, 2715 fathoms, 

 etc. in 1896, show that the Ellice Islands must be removed, while the 

 most recently published chart of Samoa to Eiji shows that the 

 former is separated from all neighbouring groups bj' a depth of at 

 least 2200 fathoms. 



Thus there is left a great plateau, including the Tongan and 

 Eijian groups, having a northward extension of 4° to 5° of latitude 

 with a depth not greater than 1500 fathoms in a general depth of 

 2000 to 3000 fathoms. Its breadth north of and including Tonga is 

 about 10°, while in lat. 9° to 13° S. it has a westward extension to 

 join the plateau on which the Santa Cruz and Solomon groups lie. 



Between lats. 10° and 13° S. are on this plateau no less than ten 

 islands, or shallow shoals. They are, from east to west, the Eookh 

 Bank, Uea or Wallis Island, the Waterwitch Bank, the Isabella 

 Bank, the Coombe Bank, Eotuma, the Alexa Bank, and three 

 other banks mentioned by Admiral "Wharton.^ Of these Uea and 

 Eotuma are high islands ; while all the rest, with the possible 

 exception of the Eookh Bank, are atoll-shaped shoals, with only a 

 few fathoms of water over their rims. 



In the same line many other shoals are reported, but their 

 positions are at present doubtful. Nurakita, or Sophia Island, 

 however, in lat. 10° 45' S., long. 179° 25' E., probably belongs to 

 the same. It is evidently on a very large shoal-bank, which the 

 numerous soundings in the area make about 60 miles long by 30 

 broad. Sufficient, however, have been shown to indicate that along 

 this line there appears to be a range of mountains varying in height 

 above the general plateau of from 5000 to 8000 feet. 



The general chart of the island shows that it consists of two 

 parts, joined together by a very narrow neck of land, which tradi- 

 tion states to have been formed by the islanders on an intervening 

 reef. It consists entirely of sand ; the mountain bounding it to the 

 west shows at its base signs of wave-action ; there are no large trees 

 on it, and in the reef a pool, 8 to 12 fathoms deep, lies in a direct line 

 between the two largest passages on the northern and southern sides. 

 Taking these as supporting this idea, I propose to treat these parts 

 separately as the eastern and western ends. Off the island to the 

 west, at a distance of 2 to 4 miles, lie three smaller islands, Uea, 

 Hatana, and Hoflewa, in a line from north-east to south-west. 



The Eastern End. 



f. This part is very rectangular in shape, but slightly pointed at its 

 western end ; its long axis runs almost . due east and west. It is 



' ' Nature/ vol. Iv. (1897) p. 390. 



