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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 for a 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. 





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