434 THE UNFINISHED BOOK. [1856 



the -opposite sides of the inter-tropical regions, short as the 

 distance is compared to the range of marine mollusca, in un- 

 interrupted seas ; hence I infer that Africa has existed since 

 our present species were created. Even the isthmus of Suez 

 and the Aralo -Caspian basin have had a great antiquity. So 

 I imagine, from the tertiary deposits, has India. In Austra- 

 lia the great fauna of extinct marsupials shows that before 

 the present mammals appeared, Australia was a separate con- 

 tinent. I do not for one second doubt that very large por- 

 tions of all these continents have undergone great changes of 

 level within this period, but yet I conclude that fundament- 

 ally they stood as barriers in the sea, where they now stand ;, 

 and therefore I should require the weightiest evidence to 

 make me believe in such immense changes within the period 

 of living organisms in our oceans, where, moreover, from the 

 great depths, the changes must have been vaster in a vertical 

 sense. 



Secondly. Submerge our present continents, leaving a few 

 mountain peaks as islands, and what will the character of the 

 islands be, Consider that the Pyrenees, Sierra Nevada, Apen- 

 nines, Alps, Carpathians, are non-volcanic, Etna and Caucasus, 

 volcanic. In Asia, Altai and Himalaya, I believe non-vol- 

 canic. In North Africa the non-volcanic, as I imagine, Alps 

 of Abyssinia and of the Atlas. In South Africa, the Snow 

 Mountains, In Australia, the non-volcanic Alps. In North 

 America, the White Mountains, Alleghanies and Rocky 

 Mountains some of the latter alone, I believe, volcanic. In 

 South America to the east, the non-volcanic [Silla ?] of Ca- 

 racas, and Itacolumi of Brazil, further south the Sierra Ven- 

 tanas, and in the Cordilleras, many volcanic but not all. Now 

 compare these peaks with the oceanic islands ; as far as 

 known all are volcanic, except St. Paul's (a strange bedevilled 

 rock), and the Seychelles, if this latter can be called oceanic, 

 in the line of Madagascar ; the Falklands, only 500 miles off, 

 are only a shallow bank ; New Caledonia, hardly oceanic, is 

 another exception. This argument has to me great weight. 

 Compare on a Geographical map, islands which, we have 



