326 
paleontological geology 
during such times as the melting of the continental ice-sheet the 
rate of discharge may have been much higher, possibly twice as 
much, in which case the time involved would be only half this 
figure. Just what were the temperatures of the oceans and the 
rivers is unknown; but even if all the water entering the oceans 
was glacial melt, which we know was far from being the case, 
the annual lowering of the average temperature of the oceans 
could only be 1-22375 of difference in degrees centigrade per year. 
As the area of unglaciated land during Permian glaciation was 
much greater than the glaciated area, and did not have a severe 
climate, the run off from this unglaciated area of large volumes of 
water at relatively high temperatures would offset to a large de¬ 
gree the cold water from the melting ice-sheet, and the actual 
lowering of the ocean temperature would be of considerably small¬ 
er magnitude, possibly only 1-50,000 or 1-100,000 of the difference 
in degrees centigrade. 
It has also been assumed for the purpose of calculation that 
the oceans neither absorbed nor radiated heat energy during the 
time that colder waters from melting glaciers were being received. 
Inasmuch as the sun was radiating heat continuously during this 
period such assumption cannot be true of the oceans, and still 
less so of the inflowing rivers. As soon as the oceanic temperature 
was lowered the rate of evaporation was lowered and a portion of 
the radiant energy of the sun, formerly utilized for evaporation, 
would be available for warming. This factor would constantly 
oppose the lowering of temperature due to the influx of cold water 
and slow down or counterbalance this cooling. 
Aside from the foregoing calculations it may be remarked that 
the best opinion as to the age of Permian glaciation places it in 
the early part of the period. If this be the true age then the 
Tetracoralla survived this event along with the rest of the floras 
and faunas, just as so many organisms survived the Pleistocene 
glaciation. 
Conclusions are: (1) That in the maximum of the first case 
there could be a drop of 5 degrees, which does not appear to be 
competent to lower the oceanic waters of the entire globe suffic¬ 
iently to exterminate all of the Tetracoralla; in the minimum of 
the first case, it is absolutely unimportant biologigally. (2) When 
we consider the second case it is seen that under the most favor- 
