

124 FACTS AND FANCIES 



be compared to the casting of aces a hundred 

 times in succession, and are so infinitely small 

 as to be incredible under any other supposition 

 than that of intelligent design. 



5. The progress of life in geological time. 

 Just as the growth of trees is promoted or 

 arrested by the vicissitudes of summer and 

 winter, so in the course of the geological his- 

 tory there have been periods of pause and ac- 

 celeration in the work of advancement. This 

 is in accordance with the general analogy of 

 the operations of nature, and is in no way at 

 variance with the doctrine of uniformity already 

 referred to. Nor has it anything in common 

 with the unfounded idea, at one time enter- 

 tained, of successive periods of entire destruc- 

 tion and restoration of life. Prolific periods 

 of this kind appear in the marine invertebrates 

 of the early Cambrian, the plants (Figure 6) 

 and fishes of the Devonian, the batrachians of 

 the Carboniferous, the reptiles of the Trias, the 

 broad-leaved trees of the Cretaceous, and the 

 mammals of the early Tertiary. A remarkable 

 contrast is afforded by the later Tertiary and 

 modern time, in which, with the exception of 

 man himself, and perhaps a very few other 

 species, no new forms of life have been intro- 



