13 -A-rt. 1.— M. Yokoyauia : 



In the first place, the number of species which are not 

 yet known to be Uving now, amount to 103. which make 

 ZO.1% of the whole fauna. But if we take into account 16 

 Pteropoda^^ already described by Yamakawa and Ishikawa from 

 Semata-no-Seki in Shitö and which are all living, the above per- 

 centage becomes 29.3, which is a little more than one-fourth of the 

 whole fauna. This percentage, though somewhat lower than that 

 of the Lower Musashino (about 37 /f), must still be called a tolera- 

 bly high one, if the overlying loam is really Pleistocene as is 

 believed by many. Of course, as I have stated in the case of the 

 Lower Musashino, also in this case, there is a possibility of the 

 reduction of the above percentage by the discover}^ of so-called 

 non-living forms as living. How far this reduction goes, it is at 

 present impossible to say. Admitting, however, that it goes down 

 to one-half which is very improbable, there still remain about 14.6% 

 of non-living forms, makmg about one-seventh of the whole 

 fauna. When we compare this percentage with those of the Crags 

 of England, for instance with the 1% of the Norwich Crag and the 

 10% of the Red Crag which are both considered as Pliocene, I can 

 not ascribe to the 3Ianzah'ian an age younger than the U'p'permod 

 Pliocene. Sometimes the occurrence of Elephas namadicus Falc- et 

 Cautl. is adduced against the Pliocene age of the layer. It is true 

 that this elephant which was first discovered in the Narbada Ijed of 

 India and subsequently also în China is usually considered Pleis- 

 tocene.^^ But it must be remembered that it is still uncertain wheth- 

 er it is really distinct from El. antiquus Falc. , a species which in 

 Europe is not only Lower Pleistocene, but also U'p'per Pliocene. By so 

 saying, however, I am far from denying the possibility of the layer 

 being younger. I am only viewing the matter from the present 



1) Some Pteropoda from the Neogene of Semata (Jour. Geol. Soc. Tokyo, vol. XIX, 1912). 

 The described species are Limacina iniata (d'Orb.), Olio (Crescis) acicula Eang-., Clio {Cre<cif) 

 virgula Rang.,. Clio (Styliola) suhulata Q. et Ct., Clio pyramiäata L., Clio cuspidata (Bosc ), Clio 

 balantium (Rang.), Cuvieria columella (Rang.), Carolinia (Diacria) trispinosa (Les.), Cavolinia 

 (Diacriii) quadridentata (hss:), Cavolinta longirostris (Les.), Carolinia glolosa (Rang.), CaroZmia 

 gibbosa (Rung.), Cavolini'i tridentata (Foxsk ). Cavolina uncinxta (Rang.) a d Cuvolinia tn*ie.ra 

 (Les.), all found in Japanese waters except Clio balantium which occurs only more south. 



2) Osborn seems to consider the Narbada bed Upper Pliocene. The Age of JVIanimals, 

 p. 335. 



