240 THE AURIFEROUS GRAVELS OF THE SIERRA NEVADA. 
of evidence thus brought together and compared inferences may be drawn, 
and even definite conclusions arrived at, which shall have all the weight of 
authority ; since it is not likely that a considerable number of persons, at 
different times and places, each knowing nothing of the other's doings, 
should make exactly the same misrepresentation. 
The miners, in general, do notice the occurrence of animal remains in 
their workings with some attention, and this for several reasons; chiefly, 
however, because the bones found are often of great size, and so make a 
strong impression on their imaginations. It may easily be conceived that 
the skull of a mastodon, or even a single tooth of this animal, is not an object 
likely to be passed by without notice, even by the most ignorant miner. In- 
deed, so far as our observation goes, these men almost always set a wonderful 
value on such specimens, and are often unwilling to part with them at any 
price. Hence it is that we, in some instances, have been obliged to be con- 
tent with a cast or even drawing of some unique bone or tooth, while in 
other cases the object could only be borrowed for a short time,— just long 
enough for study and comparison. 
Nearly all the animal remains obtained from the gravel deposits belonging 
to the vertebrates, our specimens have, almost without exception, been re- 
ferred to Dr. Joseph Leidy for examination and description. This was done 
from time to time during the continuance of the Geological Survey, and a 
portion of his results have been given in the volume of Geology published 
in 1865. Among the material submitted to this eminent authority in ver- 
tebrate palxontology there was nothing of human origin. In regard to 
objects belonging to this latter class, advice and information was sought 
from Dr. Jeffries Wyman, who was made acquainted by the writer with 
every step in the progress of the discovery of evidence bearing on the 
antiquity of man in California. None of this, however, has been published, 
up to the present time, and it will be given in a body in the next section 
of this chapter. Dr. Leidy’s results have been in part communicated to the 
scientific world in Geology Vol. L, as already mentioned, and the remainder 
will be found included in the elaborate volumes published by him in 1869 
and 1873.* All that it will be necessary to do, at the present time, in regard 
* The Extinct Mammalian Fauna of Dakota and Nebraska, including an Account of some Allied 
Forms from other Localities. By Joseph Leidy, M.D., LL.D. Philadelphia. 1869. Contributions to 
the Extinct Vertebrate Fauna of the Western Territories. By Professor Joseph Leidy ; the same being 
Vol. I. of the Report of the U. S. Geological Survey of the Territories. Washington. 1873. 
