Climatic Changes in Japan since Pliocene Epocb. iJ 



the variation of the quantity of carbonic acid gas in the air due to 

 the greater or less frequency of volcanic eruptions and the different 

 distribution of land and water in past times. 



Among these supposed causes, those which can be brought 

 into connection with oar Coralline Age are only three, viz., the 

 displacement of the poles, the quantity of carbonic acid gas and 

 tlie distribution of land and water; as for the others, if they were 

 ever real causes, they must have been of a more general character, 

 either affecting the whole earth at once, or at least one-half of it, 

 the Northern or the Southern Hemisphere, and not one-lialf of 

 the same hemisphere as in our case. 



That carbonic acid gas is very effective in keeping the air 

 Avarm b}^ preventing the too rapid radiation of heat from the 

 ground, is quite true. Therefore, if it is used in explaining the 

 occurrence of our Coralline Age only, it seems to work very well; 

 for we may assume that the volcanic eruptions were quite violent 

 at that time, so many active volcanoes still exist in our country. 

 But then, how can we explain the temperate climate of our 

 Miocene and the cool climate of our Pliocene, when volcanic 

 eruptions were at least equally as violent as in the later times? 

 That such was the case, we know by the profuse occurrence of 

 liparites and andésites and of their respective tuffs containing 

 either jMiocene or Pliocene fossils, tlave we any evidence that 

 the European Miocene and Pliocene were richer in volcanic 

 eruptions than ours? Can any one prove that the quantity of 

 carbonic acid gas has been increasing in Europe and decreasing in 

 Japan since the Diluvial Epoch? I think this gas, if it ever be 

 used to explain the change of climate in the past, can be more 

 advantageously applied in the case of the Pre-Tertiary or at least 

 the Pre-Miocene period, when the climate of the world was more 

 uniform throughout. 



The distribution of land and water also can hardly be said to 

 give a more satisfactory explanation ; for the Diluvial was a time 

 in which the configuration of the land was not much different 

 from the present. Looking at our Pacific side, the ocean itself 

 must then have been long in existence, since it is a great 



