July, 1836. 



ASCENSION. 



587 



sional green castor-oil plants, 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 worse parts of the Welsh 

 mountains. But scanty as the pasture appears, about six 

 hundred sheep, many goats, a few cows and horses, all thrive 

 well on it. Of native animals, rats and land-crabs swarm in 

 numbers : 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 destitute of trees, in which, and in every 

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

 Dring tells me, that the witty people of the latter place say, 

 " we know we live on a rock, but the poor people of Ascen- 

 sion live on a cinder the distinction in truth is very just. 



On the succeeding days, I took long walks and examined 

 some rather curious points in the mineralogical composition 

 of some of the volcanic rocks, to which I was guided by the 

 kindness of Lieut. Evans. On the basaltic masses, which are 

 daily washed by the tide, most curious calcareous incrusta- 

 tions have been deposited. They resemble in form certain 

 cryptogamic plants, especially the Marchantise ; their surface is 

 perfectly smooth and glossy, and their colour black, which 

 seems owing to animal matter. I have shown these incrust- 

 ations to several geologists, and not one guessed their true 

 origin. Any one would suppose that they had been the 

 product of fire, rather than of a deposition of calcareous 

 matter, now constantly undergoing a round of decay and 

 renovation from the action of the breakers. Near the 

 settlement where these incrustations occur, there is a large 

 beach of calcareous sand, entirely composed of comminuted 

 and rounded fragments of shells and corals. The lower part 

 of this, from the percolation of water containing calcareous 

 matter in solution, soon becomes consolidated, and is used 



