Permanence and Evolution. 15 



of the rock dove a fantail, I do not see how we 

 are any nearer the conclusion that in ten times or 

 a hundred times that period, these causes would 

 develop the Goura pigeon ; granting that, that 

 a millionfold as much time would evolve any 

 of the true Gallinaceae. Lyell only pointed out 

 that if a given cause elevated the bed of the 

 sea a foot in a century, the same cause con- 

 tinuing a million years would elevate it 10,000 

 feet. If we suppose the case to be strictly 

 parallel, we must suppose that as selection, 

 natural or methodical, has in 200 years 

 lengthened the carrier pigeon's bill half an inch, 

 so in 800 it might be lengthened two inches 

 and so on. Whatever we may think of this 

 argument, at any rate the thing known and the 

 thing supposed are analogous in kind ; but if 

 we, knowing only that the bill could be 

 lengthened, presumed with no other evidence 

 that its colour could be altered, we should be 

 really cutting loose from experience altogether. 



