368 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1914. 
>] 
here as they were at other places during the glacial age, and they 
were only partially washed out by the rivers of later times. They 
were left, or at least partially left, lying undisturbed in certain shel- 
tered valleys until their value was discovered by a few prospectors. 
The final process of removal, or at least -disturbance, of the old 
gravels was not long delayed after this important discovery had been 
made. 
The reason why this northern territory thus escaped the besom of 
destruction that swept other regions bare was doubtless the fact that 
the climate was so dry that there was little or no rain or snow to 
produce a great glacier. However great the cold may be at any 
place, it is obvious there can be no frozen water if the water is not 
first there to freeze. Had there either been no ice age, or else a dry 
climate during that epoch, placer deposits of gold might also be 
found in eastern Canada, Scotland, or Scandinavia, where small quan- 
tities of the precious metal occur in the local crystalline rocks, and 
the almost complete absence of alluvial gold is one result of that 
prolonged icy invasion of these countries. The deeply frozen sub- 
soil in the Klondike district is all that remains to tell us of the great 
cold of the glacial age, for there is no doubt that the ground has 
remained in a frozen state since that period, and that its covering of 
moist peat has effectually prevented it from becoming thawed by the 
warm sun in summer. 
The Yukon goldfield, so far as it has been explored, is apparently 
mainly confined to the vicinity of Dawson City, although small quan- 
tities of gold can be found in the sand of the Yukon for hundreds of 
miles up the valley. Indeed, our party panned a little gravel and 
got specks or colors of gold where the steamer stopped for fuel, 10 
miles below Big Salmon River, a tributary of the Lewes River above 
Tantalus, near the place where gold was first discovered in 1881. We 
passed an old digger who, we were told, can wash out about £2 worth 
of gold a day during good weather, when the water is low and the 
banks well exposed, in certain parts of the channel. 
Dawson City (see map, fig. 2) is situated on the alluvial flat close to 
the mouth of the Klondike, a small river which rises in the Ogilvie Range 
and flows southward and westward into the Yukon. The Bonanza 
Creek is a little stream in a deep and wide gully that enters the left 
bank of the Klondike Valley just above the confluence at Dawson, 
which is celebrated for the richness of its auriferous gravels. The 
Klondike is joined by two other tributaries on its left bank farther 
up, Bear Creek and Hunker Creek, the latter of which is by far the 
larger and more important.+ These and other streams all occupy 
smooth-sided valleys traversing an old peneplain or dissected upland 
composed of rounded hills and ridges. These smooth ridges originate 
in and branch outward from the. Dome, a round-topped eminence 
