no The American Geologist. February, 1904. 
between jitmosphere, rocks and ocean there must have been es« 
tabHshed a fair compensating adjustment between removal and 
supply of the carbon dioxide, though not an exact balance. 
Any enrichment of the air in this gas gives the atmospheric 
blanket greater power to retain the sun heat and produces 
warmer and more uniform climate, with greater moisture. De- 
pletion of the carbon dioxide makes the air more transparent to 
reflected heat, the blanket is thinner, the temperature falls, the 
moisture decreases, and areal or zonal differences of climate 
are intensified because the obliquity of the sun's rays become a 
greater proportionate factor. 
Extreme and rapid climatic changes can not occur for the 
reason that causes act slowly while effects lag, and counter- 
balancing factors as checks come into play. One of these 
checks is the ocean, which serves as a great reservoir of carbon 
dioxide, containing some eighteen times as much as the atmos- 
phere. On depletion of the atmospheric carbon dioxide the 
ocean by diffusion yields of its supply and thus helps to bring 
back the normal balance. 
If this theory of climate be true it will harmonize with 
geologic facts. Let us make a tentative application. The great 
land elevation and expansion, with mountain formation, of 
Tertiary time was accompanied, at least in the earlier periods, 
by warm climate even in the arctic region ; but it was followed 
by Pleistocene glaciation. The very remarkable glaciation 
found in Permo-Carboniferous strata of middle and southern 
latitudes followed the land expansion of the later Paleozoic and 
the formation of the Carboniferous coals. These two series of 
events seem quite clear. If other epochs of glaciation are found 
we may expect that they will have succeeded eras of broad ex- 
pansion of new lands, or other causes of carbon dioxide deple- 
tion. Seasons of aridity, with possible production of salines, 
are also the effects, of impoverishment of the atmosphere in 
carbon dioxide and moisture in less degree, perhaps, than re- 
quired for glaciation ; but aridity will usually accompany gla- 
ciation since both classes of phenomena imply unequal distri- 
bution of precipitation. Prevailing red color of the rock strata 
may also indicate comparative aridity. Seasons of warmth and 
moisture, with luxuriant plant life, should be found to follow 
eras of transgression by the sea and quiescent conditions. 
