88 THE ORIGIN OF SPECIES 



range; the teleostean fishes might formerly have had a 

 simihxrly confined range, and, after having been largely 

 developed in some one sea, have spread widely. Nor 

 have we any right to suppose that the seas of the world 

 have always been so freely open from south to north as 

 they are at present. Even at this day, if the Malay 

 Archipelago were converted into land, the tropical parts 

 of the Indian Ocean would form a large and perfectly 

 inclosed basin, in which any great group of marine ani- 

 mals might be multiplied; and here they would remain 

 confined, until some of the species became adapted to a 

 cooler climate, and were enabled to double the Southern 

 capes of Africa or Australia, and thus reach other and 

 distant seas. 



From these considerations, from our ignorance of the 

 geology of other countries beyond the confines of Europe 

 and the United States, and from the revolution in our 

 paleontological knowledge effected by the discoveries of 

 the last dozen years, it seems to me to be about as rash 

 to dogmatize on the succession of organic forms through- 

 out the world, as it would be for a naturalist to land for 

 five minutes on a barren point in Australia, and then 

 to discuss the number and range of its productions. 



On the sudden Appearance of Groups of allied Species in 

 the lowest knoiun Fossiliferous Strata 



There is another and allied difficulty, which is much 

 more serious. I allude to the manner in which species 

 belonging to several of the main divisions of the animal 

 kingdom suddenly appear in the lowest known fossilifer- 

 ous rocks. Most of the arguments which have convinced 

 me that all the existing species of the same group are 



