1836.] A TREELESS ISLAND. 483 



occasional green castor-oil plant, and a few grasshoppers, 

 true friends of the desert, may be met with. Some grass is 

 scattered over the surface of the central elevated region, 

 and the whole much resembles the worst parts of the 

 Welsh mountains. But scanty as the pasture appears, 

 about six hundred sheep, many goats, a few cwws and 

 horses, all thrive well on it. Of native animals, land crabs 

 and rats swarm in numbers. Whether the rat is really 

 indigenous, may well be doubted ; there are two varieties 

 as described by Mr. Waterhouse ; one is of a black colour, 

 with fine glossy fur, and lives on the grassy summit ; the 

 other is brown-coloured and less glossy, with longer hairs, 

 and lives near the settlement on the coast. Both these 

 varieties are one-third smaller than the common black rat 

 {M. ratius) ; and they differ from it both in the colour and 

 character of their fur, but in no other essential respect. I 

 can hardly doubt that these rats (like the common mouse, 

 which has also run wild) have been imported, and as at 

 the Galapagos, have varied from the effect of the new 

 conditions to which they have been exposed ; hence the 

 variety on the summit of the island differs from that on the 

 coast. Of native birds there are none ; but the guinea- 

 fowl, imported from the Cape de Verd Islands, is abundant, 

 and the common fowl has likewise run wild. Some cats, 

 which were originally turned out to destroy the rats and 

 mice, have increased, so as to become a great plague. The 

 island is entirely without trees, in which, and in every 

 other respect, it is very far inferior to St. Helena. 



One of my excursions took me towards the S.W. 

 < xtremity of the island. The day was clear and hot, and 

 1 saw the island, not smiling with beauty, but staring with 

 naked hideousness. The lava streams are covered with 

 hummocks, and are rugged to a degree which, geologically 

 speaking, is not of easy explanation. The intervening 

 spaces are concealed with layers of pumice, ashes, and 

 volcanic tuff. Whilst passing this end of the island at sea, 

 I could not imagine what the white patches were with 

 which the whole plain was mottled ; 1 now found that they 

 were seafowl, sleeping in such full confidence, that even in 

 midday a man could walk up and seize hold of them. These 

 birds were the only living creatures I saw during the whole 

 (lay. On the beach a great surf, although the breeze was 

 light, came tumbling over the broken lava rocks. 



The geology of this island is in many respects interesting. 



