NARRATIVE OF THE CRUISE. 301 



true volcanic bomb. Besides this lull, there were five or six others precisely similar in 

 appearance, and rising out of the same valley or depression in the ground. From the top 

 of the hill this depression could be seen to be bounded, towards the interior, by a semi- 

 circular cliff of rock, in some parts columnar, and open towards the sea. Above this 

 cliff rose the snow-covered cones and peaks of the interior, which, wherever the snow 

 had been removed, showed the same red colour and steep sides, so that there can be 

 little doubt of their being similarly formed to those on the lower ground. On leaving 

 the stream bed and returning to the eastward over the spur of the mountain, the 

 cliff had to be skirted, and it was found to consist of a light grey compact doleritic 

 rock. 



From these few observations it may be concluded that the island consists of a founda- 

 tion of older lava ruptured and surmounted by recent volcanoes. That these have been 

 active at no very ancient date is rendered probable by the perfect preservation of the 

 forms of the cones with their summit craters, and by the fact that the mossy vegetation, 

 so luxuriant at their base, and retaining this luxuriance on the certainly older mountain 

 spurs to an elevation at least equal to that of the top of the cone ascended, has as yet 

 spread up their sides only in straggling isolated patches. The evidence afforded by the 

 want of erosion deserves all the more weight when the position of the island is remembered, 

 where of necessity the rainfall must be considerable. 



The first scattered patches of snow were encountered at about an elevation of 800 feet. 

 A patch of the Cabbage was met with at 1000 feet. The highest point reached was 

 at an elevation of about 1500 feet, where patches of snow were frequent. Here 

 Ranunculus blternatus had disappeared, and where growing a little lower down was very 

 much dwarfed. The Azorella, with a few mosses, formed the principal vegetation ; but 

 the green was merely dotted over the bare rock and stones. The Azorella appeared 

 from this point to continue on for about 300 feet more, becoming scantier and scantier. 

 The absolute limit of vegetation may probably be placed at about 2000 feet. The part 

 explored was somewhat sheltered. A red cone of scoriae more exposed was quite bare 

 of green from about 1000 feet elevation upwards. 



At about 1400 feet elevation, the water in a shallow pool exposed to the sun was 

 found to have a temperature of 65° F., the temperature of the air in the shade being 44°. 

 At 900 feet a similar pool, but one which had a small stream of colder water running into 

 it from the cliff, had a temperature of 55°, the air there being 45°, while the thermometer 

 when plunged into the midst of a rounded mass of Azorella, rose to 50°. It is therefore 

 evident that these mounds retain and store up a considerable quantity of the sun's heat ; 

 and this fact probably yields a partial explanation of their peculiar form, which is that of 

 so many otherwise widely different Antarctic plants, and of some Swiss and New Zealand 

 Alpine plants (Raoulla, Haastia). No doubt power of resistance to wind is also gained 

 by the assumption of this form. 



