fttOGRfeBfl "I l'\l..i:oXtOLOGY 



whirh they have endeavoured to connect as many 

 they happened to be acquainted 

 \\i\\\. 1 do not think it would be a profitable 

 employment of our time to discuss conceptions 

 which doubtless liave had their justification and 

 even their use, but which are now obviously incom- 

 hle with the well-ascertained truths of pala 1 - 

 ontology. At present these truths leave room lor 

 only two hypotheses. The first is that, in the course 

 of tin- histoiy of the earth, innumerable specie 

 animals and plants have come into existence, in- 

 dependently of one another, innumerable times. 

 This, of course, implies either that spontaneous 

 generation on the most astounding scale, and of 

 animals such as horses and elephants, has b< < -n 

 going on, as a natural process, through all the t inn 

 recorded by the fossiliferous rocks ; or it necessit 

 the belirf in innumerable acts of creation repeated 

 innumerable times. The other hypothesis is, that 

 the successive species of animals and plants have 

 ari>. ii, the later by the gradual modification of the 

 earli< r. This is the hypothesis of evolution; and 

 the palceoiitological discoveries of the last decade 

 90 i'in]letely in accordance with the require- 

 ments of this hypothesis that, if it had not existed. 

 the palaeontologist would have had to invent it. 



I have always had a certain horror of presuming 

 to set a limit upon the possibilities of things. 

 Therefore I will not venture to say that it is im- 

 possible that the multitudinous species of animals 



