Fossils from the Upper Musashino of Kazusa and Shiuiosa. -21 



is true that there are alsu two forms which are Intherto known only 

 from tropical regions, namely : Chione mindanensis Smith of the 

 Philippines and Crassatella nmia Ad. et Rve. of Borneo. But these 

 two can hardly have any weight on the sixteen northern forms 

 Avhich constitute about 1% of the whole fauna. From this we are 

 obliged to infer that the waters on the Pacific side of CentralJapan 

 during the 3Ianzakian time were somewhat cooler than at present. 

 However, when we compare the northerly character of the Man- 

 zakian fauna with that of the Lower jMusashino, '* it is decidedly less 

 marked, for the latter contains some 20% of the exclusively north- 

 ern forms, and not a single one of the southern. This shows to a 

 certainty that the waters of the Musashino Epoch which at one 

 time"^ were tolerably cold became less so toward its end. And this, 

 must be called truly remarkable, ^-^ as in Europe just the opposite 

 was the case. There, as is well known, the climate of the Pliocene 

 time which on tlie whole was quite temperate became gradually 

 cold toward its end, and in the succeeding Pleistocene it became 

 so cold as to cause the so-called Ice-age. 



What I have stated above are plain facts as revealed by the 

 study of the Musashino fossils. Why things were so is at present 

 difficult to say. But an opinion I have, and tJiis opinion has 

 already been advanced in my paper entitled '' Climatic Changes in 

 Japan since the Pliocene Epoch. '"^^ 



1) Fossils from the Miura Peninsula, p. 22. 



2) Koshiba zone, Ibid. p. 24. 



3) Still more remarkable is the occurrence of the sc-called Coral-bed of Awa whicli I 

 take for younger than the Upper Musashino, and perhaps also younger than the overlying loam. 

 In this bed, as already pointed out in my " Climatic Changes,"' are found, besides large reef- 

 building corals, Molluscan remains which contain several exclusively tropical forms together 

 "with several others not yet known to be living. These remains will form the subject of my 

 next paper. 



4) .Tour. Sei. Coll., Imp. Univ. Tokyo, Vol. XXXII, Art. 5, 1911. 



