J^o. l.J GRAY AND HOOKER ON THE ROCKY MOUNTAIN FLORA. 77 



land. So our liues have been cast in pleasant places, and the goodly heritage of 

 forest trees is one of the consequences. 



The still greater richness of Northeast Asia in arboreal vegetation may find cxjda- 

 nation in the prevalence of particularly favorable conditions, both ante-glacial and 

 racent. 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 those islands — analogous to that 

 of Great Britain, but with the advantage of lower latitude and greater sunshine — 

 their ample extent north and south, their diversilied conliguration, 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 through 

 out the year, all probably conspire to the preservation and development of au 

 originally ample inheritance. 



The case of the Pacific forest is remarkalde and paradoxical. It is, as we know,, 

 the sole refuge of the most characteristic and wide-spread type of Miocene Conifer*, 

 the Sequoias ; it is rich in coniferous types beyond any country except Japan ; in its- 

 gold-bearing gravels are indications that it possessed, seemingly down 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 com- 

 mon both to Japan and to Atlantic North America.* Any attempted exjjlanation of 

 this extreme paucity of the usually major constituents of the forest, along with a 

 great development of the minor or coniferous element, would take us quite too far, 

 and would bring us to mere conjectures. 



Much may be attributed to late glaciation;t something to the tremendous out- 

 pours of lava which, immediately before the period of refrigeration, deeply covered a 

 very large part of the forest area ; much to the narrowness of the forest belt, to the 

 want of summer rain, and to the most unequal and precarious distribution of that of 

 winter. 



Upon all these topics questions open which we are not prepared to discuss. I have 

 done all that I could hope to do in one lecture if I have distinctly shown that the 

 races of trees, like the races of men, have come down to us through a prehistoric (or 

 prenatural-historic) period ; and that the explanation of the present condition is to 

 he sought in the past, and traced in vestiges, and remains, and survivals ; that for 

 the vegetable kingdom also there is a veritable archaeology. 



* 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. — Deter- 

 mination of fossil leaves, &c., such as these, may be relied on to this extent by the 

 general botanist, however wary of specific any many generic identifications. These 

 must be mainly left to the expert in fossil botany. 



t Sir Joseph Hooker, in an important lecture delivered to the Boyal Institution of 

 Great Britain, April 12, insists much on this. 



