ORGANIC GEOLOGICAL DYNAMICS. 561 



CHAPTER VI. 



PROGRESS OF THE GEOLOGICAL DYNAMICS OF ORGANIZED 



BEINGS. 



Sect. 1. Objects of this Science. 



T)ERHAPS in extending the term Geological Dynamics to the causes 

 J- of changes in organized beings, I shall be thought to be employing 

 a forced and inconvenient phraseology. But it will be found that, in 

 older to treat geology in a truly scientific manner, we must bring toge- 

 ther all the classes of speculations concerning known causes of change; 

 and the Organic Dynamics of Geology, or of Geography, if the reader 

 prefers the word, appears not an inappropriate phrase for one part of 

 this body of researches. 



As has already been said, the species of plants and animals which 

 are found embedded in the strata of the earth, are not only different 

 from those which now live in the same regions, but, for the most part, 

 different from any now existing on the face of the earth. The remains 

 which we discover imply a past state of things different from that 

 which now prevails ; they imply also that the whole organic creation 

 has been renewed, and that this renewal has taken place several times. 

 Such extraordinary general facts have naturally put in activity very 

 bold speculations. 



But it has already been said, we cannot speculate upon such facts in 

 the past history of the globe, without taking a large survey of its pre- 

 sent condition. Does the present animal and vegetable population 

 differ from the past, in the same way in which the products of one 

 region of the existing earth differ from those of another ? Can the 

 creation and diffusion of the fossil species be explained in the same 

 manner as the creation and diffusion of the creatures among; which we 



o 



live ? And these questions lead us onwards another step, to ask, 

 What are the laws by which the plants and animals of different parts 

 of the earth differ ? What was the manner in which they were origi- 

 nally diffused ? Thus we have to include, as portions of our subject 

 VOL. II. 36. 



