CONTRIBUTIONS TO THE NATURAL HISTORY OF ALASKA. l£ 



upon and matted together by the roots of grasses which thrive on the lower lands, and which 

 having fulfilled all the requirements of nature, are prostrated to the earth, not to rapidly 

 decay, but even for years to remain and help bind the few particles of soil together lest it falls 

 between the interstices of the gravel bed below. In the Yukon District it is almost impossible tc 

 find pure soil ; the particles on being dried and separated reveal undecomposed vegetable fibers, 

 and disintegrated volcanic scoriae. This character of soil made it necessary that we should fre- 

 quently moisten our garden-beds at Saint Michael's lest they blow away. 



VEGETATION. 



The scanty growth of plants, other than mosses, is due to the great accumulations of sphagnum, 

 which, in the localities favorable for its growth, reaches a depth of 6 to 80 inches in the extremely 

 depressed areas, and forming a covering, which, by its non-conductivity of heat, prevents the warm 

 rays of the sun from penetrating to the frozen stratum below. Drainage being imperfect is a 

 principal cause of the constantly frozen ground. Water remains in certain localities of extended 

 area for ages, while at the bottom is in most instances to be found a thin deposit of mud resting 

 on either frozen soil or pure ice. In walking over the low tracts I have frequently felt the 

 ground undulate beneath me like a sheet of thin ice when walked upon. Frequent, small rounded 

 holes were found of only a few inches in diameter. Into these holes I have often stepped and gone 

 down to a depth of over 2 feet, and prevented from going farther by the hole being too small to 

 admit my body. Having one day shot a duck, which mysteriously disappeared, I went to the 

 edge of the pond and looked for the bird. I then thrust a long stick under the edge of the sod 

 resting on the water of the pond, and could feel with but little interference from grass-roots far 

 in under, yet the water was too deep for me to touch the bottom of the pond. I now saw that 

 the margins of the ponds were being gradually encroached upon by the matting of the grasses, 

 which in the course of time would entirely cover the surface, and in their turn be succeeded by a 

 growth of sphagnum, which by its retention of cold would prevent the ice formed in the water 

 below from being thawed out, and by the accumulation of vegetable matter on its surface decrease 

 the power of* the summer's sun to melt the frozen lake for more than a few inches of its depth. 

 These lakes of ice have been the source of the ice bluffs presented on various parts of the coast, 

 especially north of Bering Strait, the accumulation of soil on them producing the wonderfully 

 attractive masses of plants and flowers spoken of by Arctic voyagers. 



Another cause that may influence the speedy freezing, and- consequent non-thawing of the 

 coast line and moorlands is the fact that the annual snow-fall is probably only half as much or a 

 third less than in the interior, comparatively adjacent. The greater part of the snow which falls 

 on the coast is immediately drifted either into the sea or else far inland. It is rare that a depth 

 of more than 18 inches of snow is found on the low level coast lands. Scarcely a day from 

 November to April passes but that the snow is drifted. The ravines, gullies, and abrupt hillsides 

 are the first to fill up, and by the middle of December the general character of the snow-sheet is 

 level, only interrupted by bluffs and steep hillsides. Those places where the snow collects iutothe 

 deeper drifts are found to be the scene of the more luxuriant vegetation in spring. 



With these facts it would seem incredible that flowers should appear in this apparently bleak 

 and desolate region. 



The mantle of snow has scarcely disappeared in spring than the whole surface of the earth is 

 awakened, numerous plants flourishing under such circumstances, existing, it would seem, independ- 

 ent of terrestrial heat, and in the course of a few weeks surprise is changed into wonder at the 

 luxuriance and beauty of the vegetation, equaled only in more favored climes. With the sun 

 above the horizon throughout the twenty-four hours the growth of plants is rapid in the extreme. 

 The snow has hardly disappeared before the tiny but hardy Dodecatheon has in twelve days from 

 its birth passed through the successive stages of growth, flowering, and the formation of its fruit. 

 The Pediculares in a short ten days have shot up several inches, and though the leaves are not yet 

 formed, the brighter pink raceme is full of bursting flowers. By the middle of July (and the snow 

 sometimes continues falling to the middle of June) epilobiums, anemones, asters, ranunculuses, 

 and dozens of gaudily colored plants enliven and variegate the earth. During the long Arctic 

 days the plants have their period of sleep, short, though as plainly marked as in the tropics. 



