Dr. H. Tube — New Pleistocene Fauna from lokyo. 215 



This consideration finds support in the evidence afforded by the 

 shell-sand exposed beneath the sandy gravel bed in the cutting of 

 the Yamanota line at Tabata ; it has already been pointed out that 

 the fossil remains from the shell-sand exhibit a certain resemblance 

 to the Narita fauna. As it is foxxnd quite isolated in the district in 

 which the Oji fauna occurs — I mean by this the molluscan fauna 

 of the principal shell-bed of Oji and Sbinagawa — it is of course not 

 in the typical development of the Narita fauna as would reasonably 

 be expected, but on the contrary it shows a partial similarity to the 

 Oji fauna, as indicated by the absence of Echinorachnius mirabilis and 

 Tapes aff . philippinariwi and by the frequency of Pecten toh/oensis ; 

 the two former species are very abundant in the typical shell-sand 

 of the Narita Series and very seldom found in the Oji fauna, whilst 

 the latter bears quite a reverse relationship. Briefly, the new Tabata 

 fauna seems to show the characteristic features of the Oji and Narita 

 faunas in combination, which have hitherto been found geographically 

 quite separate from each other. This indicates that the life assemblage 

 belongs to a transitional type between the Oji and Narita fauna in 

 regard to both geological and geographical distribution. 



About the subdivision of the Diluvial deposits (including Pliocene ?) 

 in Tokyo and their correlation with the European standard, various 

 propositions have been made, among others, by Messrs. Brauns, 

 T. Suzuki, and Tokunaga. Professor Brauns, 1 who identified many 

 of the molluscs from the shell-bed of Oji and Shinagawa with the 

 English Crag forms, claimed the shell-bed to be of Pliocene age, and 

 considered the wavy surface of the shell-bed as indicating a significant 

 strati graphical gap between this and the overlying bed. As a con- 

 sequence, he adopted the following subdivisions: (1) Upper Diluvium 

 — loam ; (2) Lower Diluvium — sandy gravel beds with an intercalating 

 clay-bed ; (3) Pliocene — shell-bed of Oji and Shinagawa and the 

 underlying gravel and sand beds. Mr. Suzuki 2 differed from Brauns 

 in regarding the clay and sand bed& overlying the shell-bed as 

 Pliocene, while Mr. tokunaga, in his detailed study of the fossils, 

 Avas of opinion that the shell-bed of Oji and Shinagawa as well as 

 the overlying sand and clay beds, yielding many fossils at Tabata as 

 mentioned before, must be of Pleistocene age; he considered these 

 beds as forming altogether a complex, but without referring to its 

 relation with the covering sandy gravel bed. 



My personal observation about the question led me to conclude that 

 the statement of Brauns regarding the loam and the underlying rock 

 series is correct, but about the other line of boundary Suzuki and 

 Tokunaga' s opinions are to be preferred. 



I have already often used the name Farita Series for the complex 

 underlying the loam and chiefly composed of sand and gravel beds 

 with some intercalation of thin clay layers at various horizons; for 

 the lowest complex I now wish to propose the name Tokyo Series; 

 the latter consequently includes the principal shell-bed of Oji and 



1 " Geology of the Environs of Tokio " : Mem. Sci. Dept. Tokio (University), 

 1881, No. 4, p. 77. 



8 Explanatory Text to the Geological Sheet, Tokyo, 1887 (issued by Geol. 

 Surv. Japan). 



