174 PROCEEDINGS OF THE CALIFORNIA 
laden air from the warmer ocean that probably existed far on into the glacial 
epoch.* ; 
Should the facts above stated admit of the interpretation I have given them, 
it is evident that they are inconsistent with the views of those who regard 
the glacial epoch as the result of mere geological changes in the distribu- 
tion of land and water. That these changes may have played a subordinate 
part in intensifying the influence of cosmical causes is probable, just as the 
immense outflows of voleanic rocks, covering so many thousands of square 
miles of our continent to the depth of 1,800 to 2,000 feet, must have exerted 
a great influence on the warmer climate of the Miocene. In fact, as I have 
before stated to the Academy, I believe the heated term of the Miocene is 
much more easily referable to geological causes than is the cold of the glacial 
epoch. 
Without wishing to attach too much importance to the facts above stated, I 
think the evidences of glacial action at the head of Johnson’s Pass are in- 
consistent with any other hypothesis than that, far on in the glacial epoch, 
cold winters, with heavy snow-falls, alternated with very hot summers; and 
also that, at the same period, there was no permanent ice-covering on the 
surface at an elevation of 7,000 feet above the sea, at least in these latitudes. 
It is, I think, only in such climatic conditions that the vast moraines at the 
head of Johnson’s Pass could have been formed, particularly the embank- 
ment moraine on the north side of Andrean Lake. This moraine could not 
have been formed by a glacier pushing its end out into water, as Professor 
LeCompte has shown was probably the case with similar moraines in Lake 
Valley and Mono Lake. The only conditions under which the moraine on 
the south side of the American Valley could have been formed was, that the 
surface on which it rests was not covered by ice at the time the Lake Valley 
glacier had reached the level of the head of the pass. The glacier from the 
head of Lake Valley, by far the largest entering the valley, then deposited a 
lateral moraine, stretching some distance across the head of the American 
Valley. As the ice accumulated in Lake Valley, and began to deflect the 
Echo Lake glacier to the west, the glacier from the south end of the valley 
was also forced in the same direction, depositing its moraine where the sur- 
face was still uncovered by ice, and thus laying the foundation on which 
moraine matter subsequently lodged, as the rapidly melting ice during the 
summer months exposed its surface, even after the rest of the valley was 
permanently covered with ice. 
The accompanying rough plan shows the deposition of moraine matter at 
*It is probable that a glacier has extended some distance down the American Valley 
below the point indicated, but this I believe to have been later in the glacial epoch, when 
the glaciers at the head of the valley were possibly diminishing in thickness, and after the 
great ice sculpturing in the higher mountains had been effected. I believe that it was in 
the earlier stages, and during the height of the glacial epoch, that the principal ice sculp- 
turing took place, caused by the sudden and great alternations of temperature. The 
moraine matter deposited by the retreating glaciers was evidently very slight, in com- 
parison with that deposited whilst they were increasing. 
