PREHISTORIC MAN IN CALIFORNIA. 25 



geological survey have clearly demonstrated the fact that man 

 was contemporaneous with the mastodon and elephant, since 

 the works of his hands have been repeatedly found in such 

 connection with the bones of these animals that it would be 

 impossible to account for the facts observed on any other 

 theory. In the case of the skull now laid before the Academy, 

 the geological position to which it must be assigned is appar- 

 ently still lower than that of the mastodon, since the remains 

 of this animal, as well as the elephant, which are so abund- 

 antly scattered over this State, are always (so far as our 

 observations yet extend) limited in their position to the super- 

 ficial deposits, and have never been found at any considerable 

 depth below the surface. There is every reason to believe 

 that these great proboscidians lived at' a very recent date, 

 geologically speaking, and posterior to the epoch of the exist- 

 ence of glaciers in the Sierra Nevada, and also after the close 

 of the period of activity of the now extinct volcanoes of that 

 great chain. In fact they belong to the present epoch. The 

 bed, on the other hand, in which this skull was found, must 

 have been deposited at a time when the volcanoes of the Sierra 

 were still in vigorous action, and as seems to us highly prob- 

 able from a careful consideration of the geological structure 

 of the region, previous to the glacial epoch of the Sierra, and 

 also previous to the erosion of the canyons of the present 

 rivers. No pains will be spared, however, to investigate all 

 the conditions of the occurrence of this skull, and they will 

 be fully reported at a future time. 



The portions of the skull which are preserved are, the 

 frontal bone, the nasal bone, the superior maxillary bone of 

 the right side, the malar bones, a part of the temporal bone of 

 the left side with the mastoid process, and the zygomatic 

 process, and the whole of the orbits of both eyes. The base of 

 the skull is embedded in a mass of bone breccia and small 

 pebbles of volcanic rock, incrusted with a thin layer of car- 

 bonate of lime, which appears once to have extended over the 

 whole surface of the skull, and of which a considerable por- 

 tion still remains, the rest having been removed apparently 



