424 SLEPHENAR CAPPS 
unusually free from moraine except for a zone along either side, 
and white ice shows all the way to the lower end. From favorably 
situated points along its sides the lower 20 miles of the glacier may 
be seen, but above this a bend in the valley cuts off the view. A 
number of tributary ice streams may be seen joining the main 
glacier from either side. Above the bend the extent of the Kahiltna 
Glacier is not known, but the great size of the lower portion indicates 
that the supply basin must be large. It doubtless extends to the 
crest of the range, and probably includes the southern slopes of 
Mount Foraker. In all, this glacier is probably at least 35 miles 
long, and its area, including the many headward tributaries, must 
be well over too square miles. 
An examination of the lower end of Kahiltna Glacier shows that 
the edge has probably been about stationary fora long time. There 
are no important recessional moraines to be seen, and spruce trees 
many inches in diameter grow close to the glacier front. The 
ice edge must, therefore, be as advanced as at any time for at least 
one hundred years. 
A number of streams which themselves head in glaciers enter 
Kahiltna Valley from the east above the terminus of the glacier, — 
the waters disappearing beneath the ice, or joining the marginal 
streams. Among these separate, smaller ice fields are the unusually 
beautiful ones at the heads of Granite and Hidden creeks (Fig. 2). 
Glacio-fluvial deposits and moraines: Below Kahiltna Glacier 
the stream flat shows a bare expanse of gravel bars nearly 4 miles 
wide at the glacier, and the turbulent river flows across this aggrad- 
ing flood plain in a complex of constantly shifting channels. The 
materials are coarsest near the glacier, and become progressively 
finer down stream. As the distance from the ice front increases 
the width of the bare flat is diminished by the encroachment of 
spruce timber and shrubs from either side. About 17 miles from 
its source the stream gathers into a single channel and enters a 
postglacial gorge to which it is confined for much of the remainder 
of its course to the Yentna. Glacio-fluvial terraces are not con- 
spicuously developed along the Kahiltna, but the interstream 
areas bordering the river are covered by a coating of glacial till 
and morainic material of varying thickness (Plate I). 
