1893.] Geology and Paleontology. 815 
tion. Ordinarily, also, pine trees, overwhelmed as this original forest 
was, would not survive more than thirty years. In the conditions of 
this dry climate two hundred years is a long time for them to remain 
exposed to the air without complete decay. 
“ The demonstration of so much volcanic activity at so recent a date 
in California renders it altogether likely that other eruptions will occur 
in that region in process of time, and that others have occurred at no 
great distance in the past. Previous to the eruption of the year 79, 
there was no historic record that Vesuvius had been an active volcano, 
and at a later period—between the fourteenth and seventeenth cen- 
turies—more than three hundred years elapsed without any serious 
eruption. It will be a matter of surprise if the volcanic forces west of 
the Rocky Mountains do not yet assert themselves with greater or less 
vigor. These investigations of Mr. Diller, therefore, show the possi- 
bility of bringing down to a reasonably modern period the date of the 
remains of man which have been found under the lava in various 
places on the Pacific Coast. ; 
“ Even Table Mountain in California might seem to yield a modern 
chronology in view of one fact brought out by Mr. Diller. It has 
been supposed that all of the erosion of the deeper valleys about Table 
Mountain- has been subsequent to the time when this lava stream 
filled up the old channel of the Stanislaus River. In the light of Mr. 
Diller’s observations, however, it would seem possible to suppose that 
the Table Mountain lava flow did not always follow the lowest channels 
open to it, but that it may have built up for itself obstructions in 
front of which it might turn aside to occupy abandoned channels of 
the old river at a higher level. This, at any rate, was a theory which 
suggested itself to me a year ayo, as I examined the country about ten 
miles above Sonora, where the Table Mountain stream of lava crosses 
to the left side of the present Stanislaus. That the theory suggested to 
my mind in reference to the Table Mountain flow might have been a 
fact would seem no more strange than the actual course of some of the 
streams of lava which Mr. Diller has traced from the Cinder Cone so 
carefully studied by him. He says: ‘At first the main stream flowed 
to the southeast, but gradually turned around to the left, until its 
direction was slightly west of north, where, though having flowed a 
total distance of three miles, the cessation of its flow was not more than 
a mile and a half from the vent. This course was not determined by 
the original configuration of the land, but by the obstructions to the 
later streams furnished by the cooling of earlier streams.’ 
