364 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



(always attended -with some difference, especially under 

 changed conditions), and the supposition of a common re- 

 mote ancestry is the readiest method of explaining these 

 similarities in so remote floras. In a discussion of this sub- 

 ject in 1859, Dr. Gray considered this ancestral vegetation 

 as occupying in the pliocene, or a still earlier period, the 

 then temperate high northern regions of the earth. The 

 glacial period which followed, extending southw^ard, drove 

 this vegetation gradually before it, while the differences of 

 climate, which marked, then as now, different longitudes, de- 

 termined the survival or destruction of species and the de- 

 grees of difference in resultant forms. Under varying or 

 similar conditions, species became modified in the same or 

 different directions. 



Recent geological discoveries, which establish the antiquity 

 of present species, have confirmed this view. The cypress 

 has been found fossil not only in the miocene of Europe, but 

 also of Spitzbergen, Greenland, and Alaska. Kemains of at 

 least three species of Sequoia, closely allied to our own, exist 

 abundantly in the same formation, showing that these and 

 kindred species were once prevalent throughout the arctic re- 

 gions, and extended southward into Central Europe and our 

 own Rocky Mountains. The Chinese Glyptostrohus and the 

 Gingko, now confined to Japan, had their near representatives 

 occupying a like wide range. The Lihocedrus of California 

 was, with the Sequoias, in Spitzbergen; and the oaks and 

 other common trees of the Atlantic States had numerous and 

 close representatives in the flora of polar latitudes. And 

 these same forms may be traced yet farther back into the 

 cretaceous period. 



The conclusion reached is that the facts justify the opinion 

 that the essential types of our actual florjf are marked in the 

 cretaceous period, and have come to us through the tertiary 

 without notable change ; that the present existing species 

 are the lineal descendants of the ancient ones; that the adap- 

 tation of vegetable life to successive times and changed con- 

 ditions has been maintained not by absolute recreations, but 

 by gradual modifications ; that " order and exquisite adapta- 

 tion did not wait for man's coming, nor were they ever stereo- 

 typed." An earnest protest follows against the thought that 

 such conclusions should have an irreligious tendency. As 



