INTRODUCTORY CHAPTER. xiii 



It is very remarkable, and well deserving the attention of 

 naturalists, that a species of gum-wood tree (Conyza gummifera), 

 whicli is indigenous to the climate of St. Helena, and which has 

 not, I believe, been discovered upon the opposite continent of 

 Africa, has been found upon Gough's Island and Tristan 

 d'Acunha. I have in my possession a sketch of the Island of 

 Saxemberg, upon which some trees are also represented ; of 

 what sort I am not informed. But, if it should be ascertained 

 hereafter, that they are of the same species as those on the other 

 three islands, this might be an additional reason for supposing 

 that all those islands, and perhaps Ascension, which has now no 

 trees upon it, may have been, at some remote period, united. 



If the possibility of this connection be, for a moment, admitted, 

 the question of immersion, according to M. Buifon's hypothesis, 

 might readily be solved. " History," says this celebrated natu- 

 ralist, " informs us of inundations and deluges of an extensive 

 " nature. Ought not all this to convince us, that the surface of 

 " the earth has experienced very great revolutions? Let us sup- 

 " pose, for example, that the old and new worlds were formerly 

 *' but one continent ; and that, by an earthquake, the ancient 

 " Atlantis of Plato was sunk ; the consequence of this mighty 

 " revolution must necessarily be, that the sea would rush in from 

 *' all quarters, and form what is now called the Atlantic Ocean.'' 



Having now adverted to such circumstances as appear to sub- 

 stantiate tlie opinion entertained by Mr. Forster, that St. Helena 

 must have existed above water, before it had a volcano, and was 

 afterwards violently changed, and partly subverted by subterra- 

 neous tire, it I' ay be proper to shew iu what manner this writer 

 supports and illustrates that opinion by the appearances of Ascen- 

 sion and St. Helena. 



" The dreariness of Ascension," says Mr. Forster, " surpassed 



