212 Dr. H. Yabe — New Pleistocene Fauna from Tokyo. 



Mr. Tokunaga enumerated the above list of fossils from the principal 

 shell-bearing sands and overlying argillaceous bed of Tabata. It 

 seems to me also quite reasonable that be has put together the fossils 

 from these two beds in one and the same list, for these two beds are 

 not palceontologically and stratigraphically quite distinguishable from 

 each other. 



Of the mollusca enumerated by Mr. Tokunaga, I have intentionally 

 excluded Potamides cf. incisus, Hombr. & Jacq., as it seems identical 

 with P. fluviatilis ; I also think that N~. livescens of the author (from 

 Tabata, though not from Oji) is quite different from the species 

 described by Philippi under that name. On the whole, there are 

 known from Tabata twenty- six species of Gasteropoda and fifteen 

 species of Pelecypoda(Lamellibranchia), of which the following twelve 

 are especially abundant : Nassa livescens, Potamides zonule, P. fluviatilis, 

 Rissoa cerithina, R. septentrionalis, Ringicula arctata, Martesia striata, 

 Saxioava arctica, Tellina yedoensis, Macoma nasuta, Cyclina cliinensis, 

 and Area granosa. 



Mr. Tokunaga was of opinion that the shell-beds of Oji, Tabata, and 

 Shinagawa were all of mnrine origin and of similar facies (loc. cit., p. 77, 

 footnote). This seems to me decidedly untenable, because the shell- 

 bed of Tabata is obviously a typical estuarine deposit according to the 

 previously recorded molluscs, which are in association with abundant 

 remains of land-plants, and from the lithological character of the 

 sediments; while those of Oji and Shinagawa are deposits from 

 a somewhat deeper, normally saline water, more distant from the 

 coast. Especially in the shell-bed of Shinagawa, we find abundant 

 Forarninifera and Ostracoda, both including typical plankton forms. 

 At any rate it seems certain that these three localities were at that 

 time in one and the same inlet of the sea, which was sheltered and 

 quite free from the action of breakers. 



Of an essentially different nature from the estuarine formation is 

 the shell-sand exposed at a distance of 200 metres, in the section at 

 Tabata. From the stratigraphical evidence it is quite certain that the 

 shell-sand is on the same level as the brown and blue clay of the 

 other section, and consequently represents a little higher horizon 

 than the principal shell-bed of Oji and Shinagawa. Mr. Yamakawa 

 collected and determined in the recently found shell-sand the following 

 mollusca : — 



Mollusca from the Shell-sand at Tabata. 



Gasteropoda. 



Vohitharpa perryi, Jay. 

 Nassa japonica, Adams. 

 Pleurotoma reciproca, Gld. 

 P. cf. gracilenta, Rve. 

 Natica clausa, Desh. 

 Odostomia planata, Gld. 

 Leptothyra sp. 

 Ringicula arctata, Gld. 



Lamellibranchia (or Pelecypoda). 

 Solen krusensterni, Schrenk. 

 Machaira pulchella, Dkr. 



Panopaa generosa, Gld. 

 Corbula sp. 



Myodora fluctuosa, Gld. 

 Mactra sachalinensis, Schrenk. 

 M. sulcataria, Desh. 

 Rata yoJiohamcnse, Pilsb. 

 Tresus nuttalli, Conrad. 

 Tellina venulosa, Schrenk. 

 T. nitidula, Dkr. 

 T. nipponica, Tok. 

 Saxidomus nuttalli, Conrad. 

 Venus stimpsoni, Gld. 

 Dosinia exoleta, L. 



