468 ST. HELENA. [CHAP. xxi. 



quiet old man, and such appears tho character of the greater 

 number of the lower classes. It was strange to my ears to hear a 

 man, nearly white and respectably dressed, talking with indiffer- 

 ence of the times when he was a slave. With niy companion, who 

 carried our dinners and a horn of water, which is quite necessary, 

 as all the water in the lower valleys is saline, I every day took 

 long walks. 



Beneath the upper and central green circle, the wild valleys arc 

 quite desolate and untenanted. Here, to the geologist, there were 

 scenes of high interest, showing successive changes and com- 

 plicated disturbances. According to my views, St. Helena has 

 existed as an island from a very remote epoch: some obscure 

 proofs, however, of the elevation of the land are still extant. I 

 believe that the central and highest peaks form parts of the rim 

 of a great crater, the southern half of which has been entirely 

 removed by the waves of the sea : there is, moreover, an external 

 wall of black basaltic rocks, like the coast-mountains of Mauritius, 

 which are older than the central volcanic streams. On the higher 

 parts of the island, considerable numbers of a shell, long thought a 

 marine species, occur embedded in the soil. It proves to be a 

 Cochlogena, or land-shell of a very peculiar form ; * with it I found 

 six other kinds; and in another spot an eighth species. It is 

 remarkable that none of them are now found living. Their extinc- 

 tion has probably been caused by the entire destruction of the 

 woods, and the consequent loss of food and shelter, which occurred 

 during the early part of the last century. 



The history of the changes, which the elevated plains of Long- 

 wood and Deadwood have undergone, as given in General Beatson's 

 account of the island, is extremely curious. Both plains, it is said, 

 in former times were covered with wood, and were therefore called 

 the Great Wood. So late as the year 1716 there were many trees, 

 but in 1724 the old trees had mostly fallen ; and as goats and hogs 

 had been suffered to range about, all the young trees had been 

 killed. It appears also from the official records, that the trees 

 were unexpectedly, some years afterwards, succeeded by a wire 

 grass, which spread over the whole surface.! General Beatson 



* It deserves notice, that all the many specimens of this shell found by 

 me in one spot, differ as a marked variety, from another set of specimens 

 procured from a different spot. 



t Beatson's St. Helena. Introductory chapter, p. 4. 



