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SUPPLEMENTARY SECTION" 



ON THE BEARING OP DEVONIAN BOTANY OX QUESTIONS AS TO THE ORIGIN 

 AND EXTINCTION OF SPECIES. 



[The theoretical views contained in this section, though necessary to give completeness 

 to the subject, are not suitable for an ofiScial report, and are, therefore, f 'nted separately 

 by the author, for circulation to those who may be interested in them as matters of science.] 



Fossil plants are aimost proverbially uncertain ■with reference to their 

 accurate determination, and have been regarded as of comparatively little 

 utility in the decision of general questions of palaeontology. This results 

 principally from the fragmentary condition in which they have been studied, 

 and from the fact that fragments of animal structures are more definite 

 and instructive than corresponding portions of plants. 



It is to be observed, however, that our knowledge of fossil plants becomes 

 accurate in proportion to the extent to which we can carry the study of 

 specimens in the beds in which they are preserved, so as to examine more 

 perfect examples than those usually to be found in museums. When 

 structures are taken into the account, as well as external forms, we can 

 also depend more confidently on our results. Farther, the abundance of 

 specimens to be obtained in particular beds often goes far to make up for 

 their individual imperfection. The writer of these pages has been enabled 

 to avail himself very fully of these advantages ; and on this account, if on 

 no other, feels entitled to speak with some authority on theoretical 

 questions. 



It is an additional encouragement to pursue the subject that, when we 

 can obtain definite information as to the successive floras of any region, we 

 thereby learn much as to climate, and vicissitudes in regard to the extent 

 of land and water ; and that, with reference to such points, the evidence 

 of fossil plants, when properly studied, is, from the close relation of plants to- 

 thoM-8tatk»i8 aad climates, even more valuable than that of animal fossils.- 



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