Life of Upper Lake Region. 149 



covering. The sands and dust that had cov- 

 ered them were blown to the leeward where 

 they lay in extended dunes, and this uncover- 

 ing and drifting process was still visibly going 

 on. Among these fossils we found many 

 arrow heads of obsidian such as were used by 

 recent Indians. 



We found, too, lying among them, many 

 fresh water shells of species now living in the 

 waters of Klamath marsh. Shells and .arrow 

 heads were, like the fossil bones, entirely un- 

 covered, lying upon the surface of the ground. 

 If the sands, the fossils, the arrow points and 

 the fresh water shells, were all of the same 

 period, and the camel bones were Pliocene, 

 then the arrow points were fashioneb in the 

 Pliocene and men inhabited the surrounding 

 hills in the Pliocene period. But the mixture 

 of these facts may be due entirely to the sim- 

 ple law of gravitation, for both the arrow 

 points and the recent shells may have settled 

 down among the fossils as the dust and sand 

 upon which they rested were- gradually blown 

 away. Professor Cope, on seeing the facts in 



