258 THE AURIFEROUS GRAVELS OF THE SIERRA NEVADA. 
six lines. The specimen is firm in texture and appears partially fossilized by the substitution per- 
haps of caleareous matter for some of the bone cartilage. ‘ Found under the lava at a depth of 210 
feet from the surface. From Table Mountain, Tuolumne County.” 
c. An inferior molar, apparently a fourth, resembling in constitution the corresponding tooth of 
the recent horse, but much smaller. It has lost its outer cementum and the dentine is chalky, but 
the enamel is unchanged in texture. It is about half worn, and measures internally, without the 
fangs, ten lines in length. Its fore and aft diameter at the triturating surface is eight anda half 
lines ; its transverse diameter four and three fourths lines. ‘ Found beneath the voleanic rocks, 
in gravel resting upon granite. Soulsbyville, Tuolumne County.” 
An upper molar, from an intermediate position of the series, with its outer part broken away. 
The tooth in size and constitution bears a near resemblance to some of the small equine teeth from 
the Niobrara River, Nebraska. It had just commenced to be worn. In the perfect state, it has 
measured about fourteen lines in length externally ; nine lines fore and aft ; and about eight lines 
transversely. The specimen appears partially fossilized, that is to say, some of its bone cartilage 
appears to have been substituted for earthy matter. The tooth looks as if it might belong to 
Merychippus insignis, which also has been found in Texas, as well as in Nebraska. No locality 
is marked on the specimen.* 
Section V.— Human Remains and Works of Art in the Auriferous Gravel Series. 
We come now to a most interesting portion of this volume, namely, the 
occurrence of human remains and the works of human hands in the various 
deposits which have been described in the preceding pages. And, in com- 
mencing this section, it is necessary to say a few words in addition to what 
has been previously stated in regard to the nature of the evidence which 
is here to be brought forward bearing on the question of the antiquity of 
the human race. It is true that there was a time, but few years ago, when 
no attention whatever was paid to any statements which seemed, if not to 
prove, at least to lend probability to the theory that the epoch of the ap- 
pearance of man on earth must be carried back into the shadowy past of 
geological time. The writer well remembers how, a little more than twenty 
years ago, the first statements of Boucher de Perthes in regard to the find- 
ing of flint implements in the “drift” at various localities near Abbeville, 
in France, began to be circulated in the country, and with what incredulity 
they were received.t Gradually, however, the evidence has accumulated 
from widely separated regions, until the idea of prehistoric man has become 
* But it is probably from near Sonora. 
+ The first discoveries of M. Boucher de Perthes were made in 1841, and a full account of his inves- 
tigations published in 1847. In 1854 Dr. Rigollot obtained similar results, and they were made public 
in a paper, accompanied by careful sections and drawings, iu the succeeding year. With few exceptions, 
however, these discoveries remained unknown to, or were considered inconclusive by, antiquaries and 
geologists, both in France and England, until, in 1858, Dr. Falconer, and a little later Mr. Prestwich, 
went over the ground thoroughly, and fully confirmed what had been previously published. 
