Cree Peek Eye 
RESUME AND THEORETICAL DISCUSSION OF THE PRINCIPAL FACTS CONNECTED 
WITH THE GEOLOGICAL OCCURRENCE OF THE AURIFEROUS GRAVELS. 
Section 1. — Lntroductory remarks. 
In a previous chapter of this work a brief general account of the mode of 
occurrence of the Auriferous Gravels of the Sierra Nevada has been already 
given, for the purpose of making that which was to follow intelligible to the 
reader. It now remains to present a fuller discussion of a portion at least of 
the problems involved in the gravel question, in which the object will be, to 
throw some light on the physical conditions which have had as a result the 
very remarkable deposits of which a somewhat detailed description has been 
given in the pages of this volume. 
It will be well to caution the reader, however, that an exhaustive discus- 
sion of the phenomena of the gravels is not to be expected. Indeed, such is 
the nature of geological inquiries in general, that in no branch of that science 
is there a final and absolute result to be attained. The geologist must content 
himself with slow and often hardly perceptible advances towards the ideal 
of a perfect work; he must be satisfied if he throws here and there a little 
light on doubtful points, removes a few erroneous ideas, and indicates to 
some extent the direction which future investigations should take. Further- 
more, it should be mentioned in this connection that the present volume is 
not intended to answer as a technical guide to the practical side of hydraulic 
mining. The processes employed in that kind of work are simple enough in 
theory, and the machinery not complicated ; notwithstanding this, the busi- 
ness is one which requires great experience and much caution, since the 
preliminary expenditures in such undertakings must of necessity be large, 
and difficulties are wont to occur for which only the most far-sighted are 
likely to be prepared. 
An ideal report on the gravel region, from the practical point of view, 
would demand a much larger amount of time and a vastly greater expendi- 
ture of money than have been at the disposal of the present writer. Such a 
report is not to be looked for, indeed, if by an “ideal report” we mean one 
