Xo.i.\ GHAT AND HOOKEB OH THE ROCKY IfOUNTAHl FLORA. 77 



land. So oqi lines have been oast in pleasant places, and kibe goodly heritag 

 forest trees is one of 1 1 1* • oonsequenei -. 



The still greater richness of Northeast A -i ;i in arboreal vegetation may find ezpla- 



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



The trees of the Miocene oircumpolar foresl appear to have found tl i 



. 1 1. >t 1 1< : .umI the Japanese [elands, to which most of these trees belong, most 



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



of Great Britain, but with the advantagi of lower latitude and greatei sunshine— 



their ample extent north and south, their diversified configuration, then- proximitj 



to the great Pacifie gulf-stream, by which a vast bod] of warm water Bweeps along 



their accentuated Bhores, and the comparatively equable diffusion of rain througli 



out the >far. all probably conspire to tin preservation and development of ;i i. 



originally ample inheritance. 



The ease of the Pacifie forest is remarkable and paradoxical It is, as we know, 

 the sole refuge <»t' the most characteristic and wide-spread type of Miocene Conifer®, 

 the Bequoias j it is rich in coniferous types beyond any country except Japan; in it* 

 gold-bearing gravels are indications that it p os s e s se d, seemingly down to the very 

 beginning of the Glacial period, Magnolias and Beeches, a true chestnut, Liquidambar, 

 thus, 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 explanation o( 

 ctreme paucity of the usually major constituents of the forest, along with a 

 great development of the minor or coniferou- element, would take us quite too tar, 

 aud would hriug us to mere conjectures. 



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

 pours of lava which, immediately hefore 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, aud 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- 

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

 the vegetahle 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 he 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 Royal Institution of 

 Great Britain, April 12, insists much on this. 



