288 THE AURIFEROUS GRAVELS OF THE SIERRA NEVADA. 
Finally, as the summing up of the discoveries and investigations made by 
the Geological Survey in California, we have : — 
1. The clear and unequivocal proof, beyond any possibility of doubt or 
eavil, of the contemporaneous existence of man with the mastodon, fossil 
elephant, and other extinct species, at a very remote epoch as compared 
with anything recorded in history. 
2. That man, thus proved to be contemporaneous with a group of animals 
now extinct, did not essentially differ from what he now is in the same re- 
gion and over the whole North American Continent. 
3. That there is a large body of evidence, the strength of which it is 
impossible to deny, which seems to prove that man existed in California 
previous to the cessation of volcanic activity in the Sierra Nevada, to the 
epoch of the greatest extension of the glaciers in that region, and to the 
erosion of the present river caions and valleys, at a time when the animal 
and vegetable creations differed entirely from what they now are, and when 
the topographical features of the State were extremely unlike those ex- 
hibited by the present surface. 
4. That man existing even at that very remote epoch, which goes back 
at least as far as the Pliocene, was still the same as we now find him to be 
in that region, and the same that he was in the intermediate period after 
the cessation of volcanic activity, and while the erosion of the present river 
caions was going on. 
5. That the discoveries in California, and those in other parts of the 
world, notably in Portugal and India, present a strong body of evidence 
going to prove the existence, during an immensely long period, of the 
human race in its primitive condition, — that is to say, in the simplest 
and rudest condition in which man could exist and be man. 
6. That, so far as we now know, there is no evidence of the existence 
of any primordial stock from which man may have been derived, as far 
back at least as the Pliocene. Man, thus far, is nothing but man, whether 
found in Pliocene, Post-pliocene, or Recent formations. 
