GENERAL CONCLUSIONS. 311 



General Conclusions. 



We have seen from the examples cited in the last four 

 sections, that all of the four existing great Classes of the 

 grand Division of Articulated animals, viz. Annelidans, 

 Crustaceans, Arachnidans, and Insects, and many of their 

 Orders, had entered on their respective functions in the na- 

 tural world, at the early epoch of the Transition formations; 

 We find evidences of change in the Families of these Orders, 

 at several periods of the Secondary and Tertiary series, 

 very distant from one another; and we farther find each 

 Family variously represented during different intervals by 

 Genera, some of which are known only in a fossil state, 

 whilst others (and these chiefly in the lower Classes, have 

 extended through all geological Eras unto the present time. 



On these facts we may found conclusions which are of 

 great importance in the investigation of the physical history 

 of the earth. If the existing Classes, Orders, and Families 

 of Marine and terrestrial Articulated animals have thus per- 

 vaded various geological epochs, since life began upon our 

 planet, we may infer that the state of the Land and Waters, 

 and also of the Atmosphere, during all these Epochs, was 

 not so widely different from their actual condition as many 

 geologists have supposed. We also learn that throughout 

 all these epochs and stages of change, the correlative Func- 

 tions of the successive Representatives of the Animal and 

 vegetable kingdoms have ever been the same as at the pre- 

 sent moment ; and thus we connect the entire series of past 

 and present forms of organized beings, as parts of one stu- 

 pendously grand, and consistent, and harmonious Whole. 



