SEQUOIA AND ITS HISTORY. 227 



As if, by pronouncing the cabalistic word species, the 

 question were settled, or rather the greater part of it 

 remanded out of the domain of science ; as if, while 

 complete identity of forms implied community of ori- 

 gin, anything short of it carried no presumption of 

 the kind ; so leaving all these singular duplicates to 

 be wondered at, indeed, but wholly beyond the reach 

 of inquiry. 



Now, the only known cause of such likeness is 

 inheritance; and as all transmission of likeness is 

 with some difference in individuals, and as changed 

 conditions have resulted, as is well known, in very 

 considerable differences, it seems to me that, if the 

 high antiquity of our actual vegetation could be ren- 

 dered probable, not to say certain, and the former habi- 

 tation of any of our species or of very near relatives 

 of them in high northern regions could be ascertained, 

 my whole case would be made out. The needful facts, 

 of which I was ignorant when my essay was pub- 

 lished, have now been for some years made known 

 thanks, mainly, to the researches of Heer upon ample 

 collections of arctic fossil plants. These are con- 

 firmed and extended by new investigations, by Heer 

 and Lesquereux, the results of which have been indi- 

 cated to me by the latter. 1 



The Taxodium, which everywhere abounds in the 



1 Reference should also be made to the extensive researches of New- 

 berry upon the tertiary and cretaceous floras of the Western United 

 States. Se.e especially Prof. Ncwberry's paper in the Boston Jour- 

 nal of Natural History, vol. vii., No. 4, describing fossil plants of Van- 

 couver's Island, etc.; his "Notes on the Later Extinct Floras of 

 North America," etc., in "Annals of the Lyceum of Natural History," 

 vol. ix., April, 1868; "Report on the Cretaceous and Tertiary Plants 



