306 RESUME AND THEORETICAL DISCUSSION. 
as to show clearly in what direction the former rivers flowed. The most 
westerly of these ancient streams can be traced by a series of gravel masses 
in a somewhat curving, but generally south-southwesterly direction, from 
Brandy City to Camptonville, at which point it is about six miles in a direct 
line from North San Juan. There seems to be but little doubt that these 
isolated deposits represent an old channel, and that there was formerly a 
northerly tributary coming into the main channel of the present divide be- 
tween the Middle and South Yubas from this direction. It must be noticed, 
in this connection, that the North Fork of the Yuba, which flows down the 
Sierra at first fora considerable distance in the normal southwesterly direc- 
tion, makes a sudden bend about six miles west of Foster's Bar, and thence 
flows almost south until it enters the Middle Yuba a little below North San 
Juan, thus following a channel nearly parallel with that of the ancient river, 
which formerly ran from the north by way of Brandy City and Camptonville. 
There is another nearly parallel channel about twelve miles to the west, 
which passes by Downieville through Forest City and Minnesota, and which 
formerly joined the great stream of the divide between the Middle and 
South forks of the Yuba, at a point not far from Orleans Flat, as shown on 
Plate Q. Although there are higher deposits of gravel still farther east, 
which are considered by some as indicating a third channel as coming with 
a southwesterly direction down from the vicinity of Gold Lake towards the 
Middle Yuba, it seems more likely that these are only local deposits, swept 
down from higher up on the Sierra, and not belonging to a well-developed 
channel. ) 
Between the North Yuba and the South Fork of the Feather River there 
are numerous gravel areas, some of which are of considerable extent, the 
region being one which has yielded heavily in former times, a large portion of 
the gold having, however, been obtained by drifting. Indeed, in crossing 
the North Yuba we have rather passed out of the region of the great 
hydraulic mining operations. Plates R and U show the position of the gravel 
areas near the creeks tributary to the North Yuba on the north side of that 
stream. These creeks have a general southwesterly course, and the divides 
between them are, almost without exception, covered in their highest portions 
by heavy masses of volcanic materials. The position of the gravel areas 
seems to indicate that the most important line of drainage for the ancient 
river system had a northerly and southerly direction, corresponding with 
what has been described as occurring between the North and Middle Yubas. 
