BY D. MAWSON. 415 



old crater, 2100 ft. above sea-level, is now thickly covered with 

 ash derived from subsequent outbursts, which feature has gained 

 for it the name of " great ash plain." Bounding this plain is 

 a broken line of peaks averaging almost 3000 ft. in height. 

 Towards the western side the two daughter-cones are overhung 

 by Mt. Benbow, 3720 ft., and Mt. Marum, 4380 ft., which rise 

 high above the old rim; each of these younger craters is about 

 one mile in diameter. 



Lieut. Beresford has remarked the fact that these more elevated 

 portions of Ambrym are built up of tuff and cinder beds, whilst out- 

 crops of solid lava are a more prominent feature of lower levels. 



The remains of several parasitic craters can be seen when 

 steaming round the island; a radical section through one of these 

 is beautifully exhibited on the sea-cliffs at Dip Point, where a 

 perfect cone several hundred feet in height, built up of alternat 

 ing layers of coarser and finer ejactamenta, ideally portraits the 

 interior structure of a volcanic cone. 



Malekula is the second largest island of the Group, with a 

 length of 50 miles, greatest breadth of 20 miles, and area about 

 450 sq. miles. The general topographical features of this island 

 are in striking contrast with the coral-terraced volcanic slopes of 

 the more southerly islands just considered. The whole aspect is 

 that of an older land-mass; the dome-shaped mountains of no 

 very great height (highest point Mt. Penot, 2925 ft.) with flat 

 land intervening indicate a considerable lapse of time since first 

 the land was raised above the sea and exposed to a tropical 

 denudation which since has planed down and laid bare the cores 

 of then existing lofty peaks and usurped the strippings to even 

 up the valleys, leaving a permanent record of its extensiveness 

 in thick beds of alluvium exposed in present river cuttings. 



On account of the prohibitive savagery of the natives, explora- 

 tions in this island are necessarily limited; we were, however, 

 able to examine the east coast from Port Stanley to the north- 

 ward, making several excursions well into the interior. 



Numerous small flat coral islands form an almost continuous 

 chain extending along the northern part of the east coast, distant 



