XI PALEONTOLOGY AND EVOLUTION 341 



has undergone a succession of changes which, 

 upon the whole, have been of a slow and gradual 

 character. 



2. When the fossil remains which are the 

 evidences of these successive changes, as they 

 have occurred in any two more or less distant 

 parts of the surface of the earth, are com- 

 pared, they exhibit a certain broad and general 

 parallelism. In other words, certain forms of 

 life in one locality occur in the same general 

 order of succession as, or are homotaxial with, 

 similar forms in the other locality. 



3. Homotaxis is not to be held identical with 

 synchronism without independent evidence. It 

 is possible that similar, or even identical, faunae 

 and floras in two different localities may be of 

 extremely different ages, if the term " age " is 

 used in its proper chronological sense. I stated 

 that " geographical provinces, or zones, may have 

 been as distinctly marked in the Palaeozoic epoch 

 as at present ; and those seemingly sadden ap- 

 pearances of new genera and species which we 

 ascribe to new creation, may be simple results 

 of migration." 



4. The opinion that the oldest known fossils j 

 are the earliest forms of life has no solid founda-/ 

 tion. 



5. If we confine ourselves to positively ascer- 

 tained facts, the total amount of change in the 

 forms of animal and vegetable life, since the 



