54 THE ROYAL SOCIETY OF CANADA 
bones of mammoth, bison, etc., are therefore particularly abundant in 
them. 
River Bars.—Gold-bearing gravel bars on the flanks of rivers are 
rarely found in the Klondike district itself, but they occur on many of 
the larger streams in the Yukon Territory and may be noted here 
especially as it was on these bars that gold was discovered on the Yukon 
river and its tributaries. Among these tributaries may be mentioned 
the Lewes, Pelly, Stewart, and Fortymile rivers. 
These bars have been the most recently formed of any of the placer 
deposits of the country, not excepting the gravels in the bottoms of the 
gulches, for the gulch gravels, and the bed-rock beneath them, contain 
gold which was gradually lowered down from higher levels as the 
bottoms of the gulches were deepened, while bar gravels have been 
carried to their present position and formed by existing streams, are 
entirely above bed-rock and are without connection with it. 
The processes engaged in the formation of river bars are too well 
known to need description here. Such bars are formed on the insides 
of the curves of meandering streams, and are therefore features of 
rivers which have ceased the process of downward erosion and have 
begun lateral planation and the building up of flood-plains. The gravel 
composing them, and the gold associated with it, are either derived from 
the sides of the enclosing valleys, or are brought down by the streams 
themselves from above, and deposited on the flood-plains where the 
current has decreased in velocity. 
Therefore the gold which occurs on the bars has been brought by 
the stream to its present position at a later date than that in the pay- 
streak below them. In fact, it is the gold that is now being carried into 
the stream from day to day, and is being moved along by it. 
The occurrence of rich gold-bearing bars on a stream would there- 
fore indicate that a certain amount of gold was being fed into the stream 
at the present time, and that it was being assorted and concentrated 
by it rather than that there was any rich pay-streak beneath the gravel 
on bed-rock, though the presence of these bars would not preclude the 
existence of such a pay-streak. ; 
As an example, the placer known as the Cassiar bar on the Lewes 
river may be cited. Rich gold-bearing gravels were found on the sur- 
face from which, at certain seasons, men with rockers could wash out 
from $10.00 to $20.00 a day. From this it was inferred that richer 
gravels would be found on bed-rock, and consequently a dredge, owned 
by the Lewes River Dredging Company, was installed on the property. 
The enterprise was disappointing, for, as I was informed by Mr. J. M. 
Elmer, who was in charge of the dredging operations, the gold was 
