142 THE AURIFEROUS GRAVELS OF THE SIERRA NEVADA. 
Susppivision IIJ.— THe REGION BETWEEN THE Norto Fork oF THE 
AMERICAN RIVER AND THE Soutu YuBA. 
Having, in the preceding pages, given an account of that portion of the 
gravel region of the Sierra Nevada which lies to the south of the North 
Fork of the American River, we now pass on to the consideration of the very 
important hydraulic mining districts which are found on the north of that 
stream. In describing this region, as far north as the South Yuba, the work 
of Professor Pettee will be chiefly relied on for details, as already men- 
tioned.* _ The large map, also previously referred to, of the country between 
the American and North Yuba rivers may be consulted in connection with 
this subdivision of the detailed geology of the auriferous belt of the Sierra. 
An inspection of this map will show at once the position of the gravel depos- 
its, where uncovered by volcanic materials; and it will be easily recognized 
that there are quite extensive areas which are not thus overlain. Of course 
where the gravels are covered their position cannot be indicated ; but that un- 
der the volcanic there may be almost anywhere more or less detrital material, 
containing some gold, will be readily inferred from what has been stated in 
the previous pages of this volume. Following the system already indicated, 
however, we shall defer general remarks on the occurrence of the gravels to 
another chapter, and for the present confine our observations to the details 
of their occurrence in the region under review. It is believed that by fol- 
lowing this order it will be possible to give a better and more connected 
idea of the whole series of phenomena than could be had from a description 
in which the general should precede the special. 
An examination of the map will show that directly north of the North 
Fork of the American River, and in immediate proximity to the Central 
Pacific Railroad, there is a very large deposit of uncovered gravel, on which 
a number of mining claims are indicated. This area lies in very close prox- 
imity to that lying north of Shirt Tail Cafion, and including the mining 
centres of lowa Hill, Elizabeth Town, and other camps already described from 
Mr. Goodyear’s notes. Indeed, the southern extremity of the gravel deposits 
north of the American is hardly two miles distant from the nearest gravel 
on the south side of that river, while there is good reason for believing, as 
will be noticed farther on, that these deposits, now separated by a deep. 
canon, may once have been connected. 
* See ante, p. 80. 
