146 THE AURIFEROUS GRAVELS OF THE SIERRA NEVADA. 
trict might be obtained, and thus the average yield of the gravel per cubic 
yard be ascertained; a problem which, so far as known to the writer, had, 
up to that time, never been solved for any portion of the hydraulic mining 
region of California. It was found, however, entirely impracticable, with any, 
even unlimited, expenditure of time to collect an aceurate statement of the 
location of the companies, the length of the channel held by them, and the 
depth of the gravel worked; and it was also found still more difficult to 
obtain an accurate account of the amount of gold washed out. The fol- 
lowing statement of the detailed examinations made in the vicinity of Dutch 
Flat and Gold Run is condensed and arranged from Professor Pettee’s notes. 
I found it impossible, with the time at my disposal, to collect full details of location of com- 
panies, length of channel held by each company, width and depth of gravel, or height of bank. 
And, even if the time had been unlimited, such a tabular statement for Gold Run could have 
had little or no value, for the reason that the course of the channel and the position of the bed- 
rock are entirely unknown. The claims are mostly of irregular shape, and seem to have been 
located entirely at random, or at least without any reference to the main deep channel; although 
probably some of the irregularities of boundary are owing to subsequent consolidations, and modi- 
fications after the original location. 
In the accompanying list of claims between the railroad and Indiana Hill, the measurements are 
given as roughly determined by putting a tracing of Mr. Uren’s map over a sheet of paper ruled 
in squares, each representing an acre, and estimating as nearly as possible the fractional parts of 
those squares not entirely included within the boundary lines of the claims.* 
[Here follows, in Professor Pettee’s notes, a list of forty companies, holding 737} acres, the 
names of which it seems unnecessary to give at length, and they may be omitted. | 
Since Mr. Uren’s map was made there have been some few changes in the boundaries of the 
different claims, and some consolidations and consequent disappearance of old designations, and 
introduction of new ones. ‘The measurements given are intended to include only the gravel con- 
tained within the boundary lines of the companies. In addition there is as much as seventy or 
eighty acres within the gravel limits, mostly in the ravines, but not included within the lines. 
Several rough measurements of the area included on Mr. Uren’s map, not excepting the ravines, 
were made, and results obtained varying between 825 and 875 acres. 
One of the objects in making the plane-table survey of these mines was to obtain some accurate 
data as a foundation for computing the average amount of gold contained in each cubic yard of 
gravel. I accordingly mapped the outline of the present banks, without any special regard to the 
lines of the individual claims, and determined the area of the ground actually worked over, as 
nearly as I could make it without actual tape measurements, to be : — 
Between the railroad and Goosling Ravine . : . 168 acres or 7,318,080 square feet. 
Between Goosling Ravine and Gold Run Ravine ; lit | (Seto00 = x 
Between Gold Run Ravine and Potato Ravine. Bn tol Ko 1 GLA TO. ae e 
South of Potato Ravine. 2 ; : 3 : 1444 “ 6,294,420 “ ¢ 
Total .- , =e ay * Teenoiso = 
* In Mr. J. Ross Browne’s (second) Report all the names on Mr, Uren’s map will not be found ; but 
there will be found as many as twenty additional or different ones. It is clear, in some cases, that the 
same places are referred to under different names, Mr. Uren giving the name the claim goes by, and Mr. 
Browne the names of the owners at the date of his Report ; in other cases, it is not so easy to reconcile the 
map with the Report. 
