INTRODUCTION. XXIII 



Every step in this researcih tends to convince us that the succession of strata, when 

 clearly shown, furnishes conclusive proofs of the existence of a regular sequence among 

 the earlier organisms. We are more and more able, as we advance, to observe that the 

 Author of nature, though always working upon the same plan, and producing an infinite 

 variety of forms almost incomprehensible to us, has never repeated the same forms in 

 successive creations. The various organisms called into existence, have performed their 

 parts in the economy of creation ; have lived their period, and perished. This we find to 

 be as true among the simple and less conspicuous forms of the palaeozoic series, as in the 

 more remarkable fauna of later periods. The truth of all these conclusions is now so well 

 sustained by the results of scientific investigations, that we regard the history of the past, 

 from the dawning of vitality till man assumed the dominion over the whole, as marked in 

 certain and intelligible characters, incapable of misinterpretation. 



