Survey of Northeast Greenland. 457 
also smaller drifts, with a thickness of only a few metres, exert a 
hampering effect. 
Any real protection against the cold is not offered even by the 
largest snow drifts. The temperature of the surface of the earth 
below the snow drifts must in the course of the winter, in conse- 
quence of the cold penetrating both from above and below, towards 
the surface of the earth, drop at least to the mean temperature 
of the year — in the case of Danmarks Havn — 12° to — 13°. On 
the other hand the snow drifts in the spring and early summer 
constitute an almost complete obstacle to the solar radiation. The 
soil below the snow-covered areas cannot begin to thaw, before the 
snow has almost éntirely melted away, and so only at the last stage 
of the melting process does it become able to absorb the moisture 
conveyed to it by the melting snow. The areas which only become 
devoid of snow at a late period get too short a summer; vegetation 
does not get the requisite time for its development. 
The snow drifts are the depots of the snowfall; their effect is 
similar to that of fountain heads. In order that the melting water may 
be fully exploited for the benefit of vegetation, particularly favourable 
terrain conditions are required, which may cause snow-bare land to 
become irrigated; in other words, below the drifts. or their drains 
there must be even planes with a very slight. declivity; in such 
planes bogs form, and these are, with a few exceptions, the only 
places where we may find something approaching to a large continuous 
carpet of vegetation. On stretches of this kind the drifting snow 
distributes itself fairly evenly, in a similar manner as it does on the 
fjord ice, and with a layer the dimensions of which, roughly cal- 
culated, vary between a thickness of !/ı to '/2 metre. The first falling 
snow is held fast by the vegetation, and therefore protects the latter 
against the mechanical wear and tear of the drifting snow. 
Fortunately the arctic nature has, as mentioned above, in the 
moutonnéed landform a pronounced tendency towards forming these 
almost horizontal planes, because the upper layer of earth, thawed 
and saturated with water, slides rather easily on the frozen bottom, 
which lies deeper. Small boggy tracts are therefore a rather common 
occurrence in the lowland (Basiskæret, Vesterdalen, the valley east 
of Varderyggen, the middle course of Stormelven, Ryleskæret west 
of the mouth of Stormelven), and. according as one goes in a westerly 
direction towards the inland ice, the boggy tracts gradually increase 
in frequency and size. 
This can scarcely be ascribed to chance, but it is to a certain 
extent connected with the fact that the climate towards west assumes 
a more pronouncedly continental character. 
