354 ORIGIN OF SPECIES 



/ consecutive record of their modifications could be preserved 

 L-in any one formation. 



Very many of the marine inhabitants of the archipelago 

 now range thousands of miles beyond its confines ; and anal- 

 ogy plainly leads to the belief that it would be chiefly these 

 far-ranging species, though only some of them, which would 

 oftenest produce new varieties ; and the varieties would at 

 first be local or confined to one place, but if possessed of any 

 decided advantage, or when further modified and improved, 

 they would slowly spread and supplant their parent-forms. 

 When such varieties returned to their ancient homes, as they 

 would differ from their former state in a nearly uniform, 

 though perhaps extremely slight degree, and as they would 

 be found embedded in slightly different sub-stages of the 

 same formation, they would, according to the principles fol- 

 lowed by many palaeontologists, be ranked as new and distinct 

 species. 

 I If then there be some degree of truth in these remarks, we 

 \ have no right to expect to find, in our geological formations, 

 I an infinite number of those fine transitional forms which, on 

 I our theory, have connected all the past and present species 

 Lof the same group into one long and branching chain of life. 

 r We ought only to look for a few links, and such assuredly 

 I we do find — some more distantly, some more closely, related 

 1 to each other; and these links, let them be ever so close, if 

 \ found in different stages of the same formation, would, by 

 Lmany palaeontologists, be ranked as distinct species. But I 

 k do not pretend that I should ever have suspected how poor 

 was the record in the best preserved geological sections, had 

 not the absence of innumerable transitional links between the 

 species which lived at the commencement and close of each 

 formation, pressed so hardly on my theory. 



ON THE SUDDEN APPEARANCE OF -WHOLE GROUPS OF 

 ALLIED SPECIES 



The abrupt manner in which whole groups of species sud- 

 denly appear in certain formations, has been urged by several 

 palaeontologists — for instance, by Agassiz, Pictet, and Sedg- 

 jvick — as a fatal objection to the belief in the transmutation 



