79 
cene period. ‘This uplift as already mentioned has been cited as 
the cause of the glacial climate. In the present hypothesis it is 
an incident rather than the sole cause as previously advocated. 
This uplift is known in modern literature as the Ozarkian or 
Sierrian. Its extent is shown by comparing the estimated area 
of that period 65,000,000 square miles with the 44,000,000 of the 
middle Tertiary and the 54,000,000 at the present time, an in- 
crease of 47 percent. over the mid-Tertiary. This indicates a ne- 
cessarily great change in the effective contact of the atmosphere 
with the surface of the earth. This is greater than would appear 
at first sight if we consider the contact on the surfaces of grains, 
pores and fissures. This contact becomes a rapidly increasing one 
by the sinking of the ground-water surface which was at first car- 
ried up by the uplift, but would be lowered by the trenching of the 
streams. 
Along with the increased land area there was a correspond- 
ing decrease in the sea area and a very great decrease in the shal- 
low water areas, almost to obliteration, thus producing a great 
lessening in the rate of freeing CO2 to co-operate with the in- 
creased consumption on the land in hastening the depletion of the 
atmosphere. 
There was a lowering of the temperature from these causes 
which would tend to further check the lime-secreting life of the 
ocean and at the same time give the ocean greater absorptive 
power. 
AssIGNED Causes oF GractIAL OscILLation. The as- 
signed causes are self accellerating the effect of which is to push 
the results to an extreme from which reaction will take place. 
For example: (1) A necessary consequence of the increased 
rate of transmission of CO2 to the sea along with a decreased 
rate of its release would be an accumulation of CO2 in the sea. 
(2) The cooling of the sea waters reduced the dissociation 
of the bicarbonates and hence they were more abundant than 
before. 
(3) With the increase of the snowfields there would be 
increased reflection and a decreased absorbtion of the sun’s rays. 
(4) With increasing cold there would be less rapid decay of 
