40 THE ROYAL SOCIETY OF CANADA 
In some of the higher gulches, however, and more especially in the 
upper portions of Victoria Gulch, one of the tributaries of Bonanza 
creek, where these residual sands and clays are present, they have moved 
by a creeping motion down the bottom of the gulch, and the gold has 
gradually sunk to the bottom of the loose material as it moved, so that 
in this gulch there were at one time several mining claims which con- 
tained small but rich pay-streaks of gold, and the material over-lying 
these pay-streaks was not water-worn, but was rather the slidden 
material spoken of above. 
On all the higher parts of the Yukon country above the level of the 
White Channel deposits, such residual sand and clay covers the rock 
to a varying thickness. In some cases the thickness is probably only a 
few feet, while in other cases it is much greater. I knew a shaft to be sunk 
in residual material to a depth of sixty feet, and while it is not probable 
that weathering extended much below that depth, its exact downward 
extent was unknown. 
Transportation.—As seen above on page 32, this whole country 
once formed a moderately even plain at what is now a height of about: 
3,500 feet above the level of the sea. Since that time it has been re- 
duced to its present configuration. The rocks were softened by weather- 
ing and were then transported by the agency of water down the slopes, 
and finally for the most part into the ocean. The weathering kept 
well in advance of transportation, so that the hills are still covered 
with softened rock. 
The primary force which causes this downward movement of loosened 
material is gravity, but the presence of water helps to loosen and 
separate the particles of the rock from each other, and to allow the 
force of gravity to be transformed into motion. This influence, of 
course, differs on different portions of the rock, varying according to 
the relative weights or specific gravities of the various substances. For 
instance, the force of gravity exerts a far greater influence on gold, 
which has a specific gravity of 19, than it does on quartz, which has a 
specific gravity of only 2:6. 
If water is included in the loosened or weathered rock, it causes 
it to move gently and slowly downwards. This movement is known 
as “creep,” and almost all slopes are affected by it. A typical instance 
came under my observation on one of the hills adjoining Bonanza creek. 
A narrow dyke of dark basic rock eut vertically through the light 
green chloritic schists which formed the country rock of the district. 
When within ten or fifteen feet of the top, it turned sharply sideways 
towards the face of the hill and ran horizontally until it reached the sur- 
face, being quite clearly distinguishable from the lighter coloured rock 
