ORGANIC GEOLOGICAL DYNAMICS. 573 



various stages of its progress, as geology teaches us. That they were, 

 like our own animal and vegetable contemporaries, profoundly adapted 

 to the condition in which they were placed, we have ample reason to 

 believe ; but when we inquire whence they carne into this our world, 

 geology is silent. The mystery of creation is r ot within the range of 

 her legitimate territory ; she says nothing, but she points upwards. 



Sect. 6. The Hypothesis of the regular Creation and Extinction of 



Species. 



1. Creation of Species. We have already seen, how untenable, as a 

 physiological doctrine, is the principle of the transmutability and pro- 

 gressive tendency of species ; and therefore, when we come to apply to 

 theoretical geology the principles of the present chapter, this portion 

 of the subject will easily be disposed of. I hardly know whether I 

 can state that there is any other principle which has been applied to 

 the solution of the geological problem, and which, therefore, as a gene- 

 ral truth, ought to be considered here. Mr. Lyell, indeed, has spoken 12 

 of an hypothesis that " the successive creation of species may consti- 

 tute a regular part of the economy of nature :" but he has nowhere, 

 i think, so described this process as to make it appear in what depart- 

 ment of science we are to place the hypothesis. Are these new species 

 created by the production, at long intervals, of an offspring different in 

 species from the parents ? Or are the species so created produced with- 

 out parents ? Are they gradually evolved from some embryo substance? 

 or do they suddenly start from the ground, as in the creation of the 

 poet ? 



. . . .... Perfect forms 



Limbed and full-grown : out of the ground up rose 



As from his lair, the wild beast where he wons 



In forest wild, in thicket, brake, or den ; . . . 



The grassy clods now calved ; now half appeared 



The tawny lion, pawing to get free 



His hinder parts ; then springs as broke from bounds, 



And rampant shakes his brinded mane ; <fcc. &c. 



Paradise Lost, B. vii. 



Some selection of one of these forms of the hypothesis, rather than 

 the others, with evidence for the selection, is requisite to entitle us tc 



12 B. in. c. xi. p. 234. 



