WROLHE STS OF CGACSE OF GLACIAL PERIODS: 575 
episode, dissociation is promoted, and the ocean gives forth its 
carbon dioxide at an increased rate, and thereby assists in 
accelerating the amelioration of climate. 
c. Organic action.— The elimination of the vastly preponder- 
ating percentage of calcium salts in the land waters, involving 
aureduction, froni’ 7o' per cent: in these toless than 4, percent. 
in sea waters, is assigned mainly to marine life. With the 
calcium sulphate we do not seem to be specially concerned 
here except so far as indirectly it may become involved in the 
reactions which eliminate the calcium carbonate. It would 
appear obvious, however, from the fact that its ratio is reduced 
from about 20 per cent. in the land waters to about 3.6 per cent. 
in the sea waters that it suffers much secular loss. The reduction 
of the calcium carbonate from about 50 per cent. in the land 
waters to about one third of I per cent. in the sea waters is a 
fact of prime importance. 
The amplest and most familiar geological observation shows 
that the elimination takes place mainly as normal carbonate of 
lime in the form of shells and skeletal parts of various marine 
animals, and of some plants. The gross fact of observation is 
the disappearance of great quantities of calcium bicarbonate 
from the water, and its reappearance as the secretions of animals 
and plants in the form of normal carbonate. Whatever may be 
the specific steps involved in their life economies, it seems 
essentially immaterial to consider here whether the animals and 
plants take their lime directly from the calcium carbonate, and 
set its surplus carbonic acid free, or whether they take it from 
calcium sulphate, and by using carbonic acid, derived ultimately 
from the waters also, convert it into carbonate, setting free the 
sulphuric acid to attack in turn the calcium carbonate of the sea, 
and thus by circuitous process free its carbonic acid, or whether 
the procedure follows any other indirect course; for the final 
result, when balanced all around, seems to be essentially the 
same. It may even trench on the organic cycle without essentially 
changing the final result. The important thing to be observed 
is that the process is dependent upon sea life, and varies with its 
