150 llie American Geologist. Scptomber, 1897 
[ce Margin Drainage. The land front of the glacier is a 
slope, varying in steepness, and forming one face of a valley 
whose other wall is the land, sometimes having a gentle slope 
but usually a precipitous hill side. In the valley thus formed 
there is a marginal drainage, (Plate X) with a water supply 
furnished mainly from the ice. Numerous tiny streams flow 
from the glacier top, cascading down the slope and uniting 
with the marginal stream. No single case of a subglacial 
stream emerging from beneath tlie ice was found. The melt- 
ing was entirely surface and marginal, though along tiie sea 
front it is perfectly certain that there is subglacial drainage. 
The surface melting of the crevassed glacier forms streams 
which disappear into the ice, and which come out somewhere 
below sea level ; but we were not successful in finding out 
where these emerged. 
In its passage down the valley, between the ice and the land, 
the marginal stream finally enters the sea. During its passage 
it now and then encounters tongues of ice, and for a distance 
flows along them, and finallj^ beneath them, where the glacier 
edge rests against a moraine, or the rock of the land. Again 
it falls over a rock ledge as a cascade, or even a grand water- 
fall ; and every here and there it is dammed to form a margi- 
nal lake. (Plate XI.) Dozens of these, great and small, were 
seen along the margin ; and the}' varied in size from tiny 
pools to ponds half a mile in length, and 200 to 300 yai'ds in 
width . 
Since the water of the marginal streams is everywhere milky 
with sediment, these lakes are receiving quantities of mud- 
dy deposits, and in them tiny deltas are being built. (Fig. 1, 
Plate XII.) Where the lake waters bathed the ice front little 
icebergs are coming ofl", in exactly the same way as in the 
fjord at the glacier front, and these are bearing out into the 
lake large rock fragments which are being strewn over the 
bottom or on the shores. Also at the base of the ice clitfs, as 
well as on some of the deltas formed by rapidly flowing streams, 
pebbles and boulders are being mixed with the clay. 
Nearly every lake shov/s signs of alteration in level result- 
ing from the change in outflow either to some point beneath 
the ice, when the lake ma}^ be entirely drained, or to some 
lower outlet for the lake opened by a change in the ice front. 
