Climatic Changes in Japxn since Pliocene Epoch. 9 



bed contains those which now inhabit tropical seas only. This is 

 an unmistakable sign of the very warm climate which then 

 prevailed in that part of Japan, much warmer than that of to daj^, 

 for the sea near Noma now cools down to about 10°C, while 

 the minimum temperature of the water in which the reef-corals 

 live is 19^G. Indeed I am quite sure that while the Occident was 

 buried under the heavy burden of ice millions of tons in weight, 

 Centra] Japan was exposed to the lieat of tlie tropical sun. 

 Beyond in the West, one speaks of the ice-age; here in the Far 

 East we can talk only of tlie coralline. Such being the case it is 

 quite natural that geologists should have been unable to find any 

 glacial remains in this part of the world. 



It may perhaps be asked whether in Japan there are no beds 

 which are the equivalents of the Interglacials and Postglacials of 

 the West. I think there are. Several years ago I was passing by 

 the town of Mobara in Kazusa situated on the Pacific side of the 

 Söbö Peninsula and much to the north-east of Noma, when I 

 discovered a sand-layer exposed along the two sides of a stream 

 flowing through a coastal plain at the foot of the Tertiary hills. 

 In this layer I found about sixty species of marine Mollusca all 

 living. Some of these are either tropical or are at least not yet 

 known to exist in the neighbouring seas. Such are Area symmetrica 

 Reeve, Tapes d. quadriradiata Deshayes, Venus cî. listeri Gray, Eulima 

 solida Sowerby and Suhemarginiila carinata Reeve. I also examined 

 shells brought from a sand-layer at Cape Daito, somewhat to the 

 south-east of the above mentioned place, and found them to 

 contain, besides one or two tropical forms, a species of Turritella 

 which hitherto has l)een known to occur only in the Koshiba 

 Pliocene. And as these layers contain no snch large corals as 

 those found at Noma, they must be considered to be deposits 

 of a time or tim^es in which the climate was much more 

 temperate. This leads us to ask, if they are not IntercoraUine or 

 PostcoraUine. ' ^ 



From all that I have stated above, it follows quite naturally 

 that the temperature in Central Japan has gradually increased 



1) Similar shell-layers seem to occur also on the coast between Xoma and Kachiyama. 



