252 FERNOW 



in close proximity to some of the great glaciers, showing 

 an astonishing indifference to the influence of the near-by 

 ice masses. Not only do the trees, wherever soil con- 

 ditions permit, grow close to the icy river, attaining (as 

 a measurement within one hundred yards of LaPerouse 

 Glacier showed) diameters of five feet and heights of 

 150 feet, but in places they even encroach upon the icy 

 field, when this has come to rest and has a scanty cover 

 of soil from the moraine material, upon which vegeta- 

 tion can establish itself. Thus, at the foot of Lucia Gla- 

 cier, on Yakutat Bay, the stream which runs in a wild 

 torrent from the glacier has cut a veritable canyon 1 through 

 the ice, exposing an ice bank over one hundred feet in 

 height. This ice is overlaid with moraine material a 

 foot or more in depth, and this is sufficient to support a 

 dense cover, not only of herbaceous, but of woody vege- 

 tation a thicket of the ever-present alder, with occa- 

 sional willows ; and even spruces do not find the substratum 

 too cold. As the ice melts at the border, the soil and its 

 occupants may be seen from time to time tumbling down 

 into the stream, or else into the deep potholes with which 

 we find this ice plateau amply provided. 



The other observation which I desire to record refers to 

 an example of the substitution of soil conditions for cli- 

 matic conditions. 



The beautiful Alpine hemlock {Tsuga mertensiana), 

 the embodiment of unyielding perseverance, is par excel- 

 lence the tree at timber-line throughout the Cascade and 

 Sierra Nevada ranges ; we do not expect to find it except 

 in the humid-cold atmosphere of high elevations, battling 

 with the storms in ice and snow. That single specimens 

 should occasionally find their way down among the vegeta- 

 tion of lower levels, as at Hot Springs, near Sitka, does 



1 See I. C. Russell's full description in National Geographic Magazine, Vol. 

 Ill, pp. 176-185, 1891. 



