424 THE GEOLOGY OF THE NEW HEBRIDES, 



Aurora or Maewo Island is, like Aragh Aragh, long, narrow, 

 and mountainous. It is, however, more elevated, probably 

 attaining a height of close on 4000 ft.* The dimensions are : — 

 Length, 32 miles; breadth, 3J miles; and approximate area, 

 90 sq.miles. It is probably wholly composed of volcanic rocks. 



The Banks Group lies about 50 miles to north of Aurora. 

 With the exception of some of the smallest, the islands are all of 

 volcanic origin, and, as evidenced by the fumaroles of Vanua 

 Lava, are of comparatively recent age. 



Vanua Lavaj or the Great Banks Island. — Approximate 

 dimensions are : — Length, 15 miles; breadth, 10 miles; area, 85 

 sq.miles. 



High rugged ranges of mountains run in a general north and 

 south direction, attaining a maximum elevation of 3120 ft. In 

 the north centre hot springs and fumaroles cover a considerable 

 area of ground, giving rise to hot-water creeks which, uniting 

 together, enter the sea at Port Patteson. 



The entire island appears to be composed of volcanic rocks, of 

 which porphyritic pyroxene and olivine pyroxene basalts are the 

 most abundant. Other than basic lavas, was one specimen of a 

 pyroxene andesite. 



It seems probable that Vanua Lava represents the south-west 

 portion only of a former immense crater, which included also the 

 islands of Mota and Valua. The general distribution of the 

 islands, the soundings, and the dip of the agglomerate and cinder 

 beds, all favour this view. 



Mota is a hat-shaped island 2 miles in diameter. The rim of 

 the hat, so to speak, is a broad shore-flat, in the development of 

 w-hich, coral has no doubt participated; the central peak, 1350 ft. 

 high, appears to be volcanic. 



* The Admiralty chart has it marked down as about 2000 ft., but to us it 

 seemed quite as lofty as Aoba. 



t M. Levat has reported the occurrence of gneiss and trachyte on Vanua 

 Lava; this we think is entirely a mistake. 



