232 ESSAYS. 



The still greater richness of northeast Asia in arboreal 

 vegetation may find explanation in the prevalence of particu- 

 larly favorable conditions, both ante-glacial and recent. The 

 trees of the Miocene circumpolar forest appear to have found 

 there a secure home ; and the Japanese islands, to which 

 most of these trees belong, must be remarkably adapted to 

 them. The situation of these islands — analogous to that of 

 Great Britain, but with the advantage of lower latitude and 

 greater sunshine, — their ample extent north and south, their 

 diversified configuration, their proximity to the great Pacific 

 gulf-stream, by which a vast body of warm water sweeps 

 along their accentuated shores, and the comparatively equable 

 diffusion of rain throughout the year, all probably conspire to 

 the preservation and development of an originally ample in- 

 heritance. 



The case of the Pacific forest is remarkable and paradoxi- 

 cal. It is, as we know, the sole refuge of the most charac- 

 teristic and widespread type of Miocene Coniferce, the Se- 

 quoias ; it is rich in coniferous types beyond any country 

 except Japan ; in its gold-bearing gravels are indications that 

 it possessed, seemingly clown to the very beginning of the 

 Glacial period, Magnolias and Beeches, a true Chestnut, 

 Liquidambar, Elms, and other trees now wholly wanting to 

 that side of the continent, though common both to Japan and 

 to Atlantic North America. 1 Any attempted explanation of 

 this extreme paucity of the usually major constituents of for- 

 ests, along with a great development of the minor, or conifer- 

 ous, element, would take us quite too far, and would bring us 

 to mere conjectures. 



Much may be attributed to late glaciation ; 2 something to 

 the tremendous outpours of lava which, immediately before 



1 See, especially, " Report on the Fossil Plants of the auriferous gravel 

 deposits of the Sierra Nevada," by L. Lesquereux ; " Mem. Mus. Comp. 

 Zoology," vi. No. 2. — Determinations of fossil leaves, etc., such as these, 

 may be relied on to this extent by the general botanist, however wary of 

 specific and many generic identifications. These must be mainly left to 

 the expert in fossil botany. 



2 Sir Joseph Hooker, in an important lecture delivered to the Royal 

 Institution of Great Britain, April 12, insists much on this. 



