KLONDIKE AND YUKON GOLDFIELD—CADELL., 367 
A curious and interesting feature of the district must now be 
mentioned. The numerous lakes, the deeply eroded ice-worn valleys, 
and the widespread deposits of gravel and morainic material in the 
upper part of the Yukon Basin, all tell of the former wide extension of 
the glaciers, whose diminished representatives have long ago shrunk 
back into the remote glens and corries among the higher mountains. 
But as we sail northward toward the Arctic Circle these traces of 
former extensions of land ice diminish, and finally disappear alto- 
gether. The moraines are no longer to be seen, and all we find in 
the valley is a wide deposit of very fine sand or silt, such as is washed 
in a milky flood from beneath any valley glacier. These glacial silt 
beds finally dwindle away, and the solid rock surface becomes soft and 
rotten, and covered with screes and loose débris produced entirely by 
its own disintegration. 
Long before we reach Dawson all traces of glaciation have disap- 
peared, and the noble river winds back and forward between the steep 
sides of a valley, a quarter of a mile wide, cut out of the old and 
decomposed plateau of crystalline rocks. The latitude of Dawson 
City is that of the south of Iceland, and its level is a little more than 
1,000 feet above the sea. The whole of the old alluvium in the valley 
bottoms is frozen hard to a depth of over 100 feet, and the summer 
sun is only able to thaw a few feet of the surface before the winter’s 
cold sets in, and the whole region is incased in snow and ice. 
Now, it is a matter of common knowledge that the cold was at one 
time so intense in the Northern Hemisphere that the northern parts 
of Europe and Canada were covered for a time by huge glaciers, or 
ice caps, such as now envelop the whole of Greenland. The whole of 
the Pacific coast of British Columbia and the southern end of Van- 
couver Island is intensely ice worn. In the eastern part of Canada 
the polar ice cap in the glacial period covered the country as far south 
as the Great Lakes, and left the Province of Ontario sprinkled over 
with clay and stones from far-off northern sources. Wherever the 
creat ice sheet went it swept away all the loose rock, river alluvium, 
and soil that lay on the preglacial land. The underlying rocks were 
scoured and polished, and when the ice melted at last, the valleys 
and plains were left buried under a covering, not of soil or river 
alluvium in stratified beds, but mainly of unstratified bowlder clay 
or till, produced by the grinding of the creeping ice, which was at 
places thousands of feet in depth. 
These considerations may seem remote from the subject of the 
Klondike gold deposits, but in reality the opposite is the case. The 
original valley gravels, the accumulations of long ages in which small 
quantities of gold derived from the adjacent rocks had become col- 
lected, sorted out, and concentrated by the long-continued action of 
the ancient rivers—these auriferqus deposits were not swept away 
