APPARITION OF SPECIES 101 



period that in the middle part of the Tertiary most of 

 the leading groups were represented by more nume 

 rous species than at present, while many types then 

 existing have now no representatives. At the close 

 of this great and wonderful procession of living beings 

 comes man himself the last and crowning triumph 

 of creation, the head, thus far, of life on the earth. 



If we imagine this great chain of life, extending 

 over periods of enormous duration in comparison with 

 the short span of human history, presenting to the 

 naturalist hosts of strange forms which he could 

 scarcely have imagined in his dreams, we may under 

 stand how exciting have been these discoveries 

 crowded within the lives of two generations of geo 

 logists. Further, when we consider that the general 

 course of this great development of life, beginning 

 with Protozoa and ending with man, is from below 

 upward from the more simple to the more complex 

 and that there is of necessity in this grand growth 

 of life through the ages a likeness or parallelism to 

 the growth of the individual animal from its more 

 simple to its more complex state, we can understand 

 how naturalists should fancy that here they have 

 been introduced to the workshop of Nature, and that 

 they can discover how one creature may have been 

 developed from another by spontaneous evolution. 



We need not be astonished that many naturalists 

 are quite carried away by this analogy, and appear 

 unable to perceive that it is merely a general resem- 



