UNIVERSITY OF TORONTO LIBRARY purchased for the Geology Collection from the VARSITY PALAEONTOLOGY FUND July 7th, 1922. Vol. XLIV., Art. 1 Jlv Jr|il Hi A. m & $3 m w % fa JOUKNAL OF THE COLLEG-E OF SCIENCE, IMPERIAL UNIVERSITY OF TOKYO. Matajiro Yokoyama, Fossils from the Upper Musashino of Kazusa and Shimosa. **• TOKYO. PUBLISHED BY THE UNIVERSITY. TAISHO XI. Coleman Library Department of Geology University of Toronto I Publishing Committee. • :> - < Prof. S. Goto, Riijakuhukushi, Director of the College {ex officio). Prof. M. Miyoshi, Rigakuhakushi. Prof. F. Omori, Rigakuhakushi. Prof. S. Watase, Ph. D., Rigakuhakushi. •**• All communications relating to this Journal should be addressed to the Director of the College of Science. SEP 2 9 JOURNAL OF THE COLLEGE OF SCIENCE, TOKYO IMPERIAL UNIVERSITY. VOL. XLIV., ARTICLE I. Fossils from the Upper Musashino of Kazusa and Shimosa. By Matajiro YOKOYAMA, Rigakuhahushi, Professor of Palaeontology, Imperial University of Tokyo U7r/i 17 Plates. General Remarks The Upper Musashino Formation which consists of horizontal interstratified layers of clays, sands and gravels overlaid only by a brown unstratified loam generally believed to be Pleistocene in age, though without any palaeontological evidence, forms a low but ex- tensive plateau around Tokyo whose height above the sea-level varies from a little over ten metres near the sea-coast up to more than a hundred in the interior. This plateau is variously dissect- ed by valleys along whose sides it often shows steep escarpments fairly well exposing the rock-layers of which it is composed. In these escarpments there is frequently a sand-layer more or less filled with fossils which are mainly Mollusca, and therefore usually known under the name of shell-layer which is found, not only in and around the city of Tokyo, 2) but also in Kazusa and Shimosa, 1) Explained in my paper entitled " Fossils from the Miura Peninsula and its Immedi- ate North " (Art. 6, Vol. XXXIX, Jour. Coll. Sci., Imp. Univ. Tokyo, 1920). 2) The fossils found in and around Tokyo have already been studied by David Brauns in " his " Geology of the Environs of Tokio (Mem. Sci. Departm. Tokio Daigaku, No. 4, 1885) and S. Tokunaga in his "Fossils from the Environs of Tokyo (Art. 2, Vol. XXI, Jour. Sci. Coll. Imp. Univ. Tokyo, 1906). Brauns described 87 species of Mollusca and Brachiopoda all of which he identified with the living forms and still called them Pliocene. Tokunaga recognized 168 species of Mollusca of which he found a little more than 20 not known to him as living (he says that at least 10 are surely extinct). But unfortunately he ignored many of the small- sized shells, as difficult of determination, whereby the percentage of extinct forms against, the living became not quite correct. Consequently his conclusion, drawn from it, that the layer is probably Pleistocene can not be called quite certain. It is here to be noted that most of the shells described by Brauns and Tokunaga are also found among those described by me in this paper. : O Art. 1.— M. Yokoyama : provinces lying to the east of it. The Mollusca and the Brachi- opoda described in the present paper are those obtained from the shell-layer of the latter. The position which this shell-layer occupies in the Upper Musashino is not far from the overlying loam, though at various distances from it. At Oji, a northern suburb of Tokyo, where Brauns 1 and Tokunaga obtained' a great deal of their materials, the shell- T layer is given by them as separted from loam b} layers of clays, sands and gravels which together make up a thickness of about 4,3 metres, and which, according to Tokunaga, grows to about 6,6 metres at Tabata, a place about 3 kilometres south-east of Oji, and 2) at the diminishes to about 2,5 metres at Shinagawa , a suburb southern extremity of Tokyo. At Otake, Shimosa, the interven- ing layer is a sand about 3,6 metres in thickness, while at Shit<>, Kazusa, it is between 2 and 4 metres. From these we know that the shell-layer occupies a position very near to the upper boundary of the Upper Musashino Formation. As to the thickness of the shell-layer itself, it is sometimes considerable. At ' take and Takatano-Seki, it attains a thickness of nearly 7 metres in which shells are in such close heaps that the layer is to a greater part made up of them. The loam and the underlying layers of the Upper Musashino are generally conformable with one another. But at Kido, Tega- mura, on the south bank of Tega Swamp in Shimosa, the shell- la}r er is superposed on a yellowish clay whose surface is full of deep pits and holes, and this clay which is about 1,5 metres thick on an average is again on a blue clay whose surface is very uneven. The localities from which the fossils have been collected are in all six, viz. 3) 1. Otake, Shimosa. Very near the railway station of Man- zaki on the Abiko-Sawara line. 1) I have been collecting these fossils for more than 15 years, during which time I was assist«d by several gentlemen among whom I may mention Messrs, X. Fukuchi, M. Oyu, T. Ogura, T. Matsumoto and S. Tsuboi, to whom my thanks are due. 2. The shell-layer formerly exposed at Oji, Tabata and Shinagawa is at present not acces- sible for collection. 3) Tf8EPMA£*t*1t Fossils from the Upper Musashino of Kazusa and Shintosa. 3 2. Kioroshi, Shimosa. About 14 kilometres west of Otake and close to the railway station of the same name on the same line as above. 3. Kamenari, Shimosa. 2) About 4 kilometres south-west of Kioroshi. 4. Tega, Shimosa. 3) On the south bank of the swamp of the same name and about 8 kilometres west of Kioroshi. The fossil- layer is exposed at several places of which Kido and Kizaki are the most important. 5. Shisui, Shimosa. About 8 kilometres south of Otake, and in a railway-cutting of the station of the same name on the Narita-line. 3) 6. Shito, Kazusa. At places from 1,5 to 3,5 kilometres south of the railway- station of Honda on the Boso line, which lies about 22 kilometres south of Shisui. The shell-layer is exposed at several places of which three may be mentioned, Semata-no-Seki, Takata and Takatano-Seki. The number of species of the Mollusca and the Brachiopoda collected in the above named localities amounts to 335 in all, as shown in the following table : 03 © ® OCD LIVING 00 — a o |i MOLLUSCA o CO CD Gastropoda Family Actaeonidae. 1. Solidula strigosa (Gld.) + : : : Central, Western, Southern Japan. 2. Solidula clathrata Yok. : : : :+ +++ 3. Leucotinagigantea (Dkr.) : : : Japan (Dunker). Family Tornatinidae. + : 4. Tornatina exilis Dkr. ++ Western Japan. +: 5. Tornatina longispirata + : Yam. 6. Eetusa globosa Yam. : : +:+::: 7. Eetusa truncata Yam. ++++ : : ++++ 8. Eetusa minima Yam : + Northern Japan. Philippines. 9. Volvula angustata (Ad.) : : var. N. Guinea. i) -F»Ep«fB*-F«r 2) m%&*Ltttt&J% 3) x.Mtum&ntttF, *® 4) ±« i Art. 1. —M. Yokoyania : - rS •^ - o o LIVING u d •*3 -. o Z X y M & X 10. Yolvula acutaeforniis Yok + . Family Scaphandridae Central Japan. 11. < 'vlichna inusashiensis + +......++ Tok. Family Phihnidae. 12. Philine scalpta Ad. + Central and Western Japan. 13. Philine pygniaea Tok. + Central Japan. 14. Philine takatensis Yok. + • • Family Bullidae. 15. Bulla niultiarata Yok. + • . 16. Bulla ovula Sow. + Central and Southern Japan. Fa mily Bingiculidae. 17. Ringieula musashinoensis Central Japan. Yok. Family Terebridae. 18. Terebra lischkeana Dkr. -r + + Central and Western Japan. 19. Terebra gotoensis Smith. + Western Japan. 20. Terebra hedleyi Pils. + Western Japan. 21. Terebra recticostata Yok. + + 22. Terebra chibana Yok. + + . 23. Terebra sniithi Yok. + Central Japan. 24. Terebra quadriarata Yok. + . 25. Terebra latisulcata Yok. + • • 26. Terebra suavjdica Yok. + • • 27. Terebra tsuboiana Yok. + • . + • • Central Japan. 28. Parviterebra raritans Yok. + Family Pleurotomidae. 29. Pleurotoina vertebrata + + + .... + .. Central and Western Japan. Smith. 80. Genotia pseudopannus + + . Yok. 31. Genotia ogurana Yok. + + 1 32. Drillia principalis Pils. + + . + Northern, Centra , and Western 33. Drillia subauriformis Japan. Smith. + • • + Central and Western Japan. 34. Drillia glabriuscula Yok. + • . 35. Mangilia deshayesii Dkr. + + • • + Central and Western Japan 36. Mangilia ojiensis Tok. + . 37. Mangilia fukuchiana Yok. + Central Japan. 38. Mangilia (Cythara) rugo- + solabiata Yok. 39. Mangilia (Cythara . + oyuana Yok. Fossils from the Upper Musashino of Kazusa and Shimosa. LIVING 40. Bela.rugulata Tros. var. (Fossil in English Crag). schneideri Harm. 41. Bela recti cost ulata Yok. Family Cancellariidae. 42. Cancellaria spengleriana + .. + + + + + From Central Japan to Aus- Desh. tralia. and Western Japan. 43. Cancellaria nodulifera + . + . + + Central Sow. Central Japan to Philip- 44. Cancellaria asperula Lam. + + + • • From var. reeveana Crosse. pines. Family Olividae. 45. Olivella fortunei (Ad.) + + + + + + •• Central Japan, China. 46. Olivella spretoides Yok. + . 47. Ancilla hinoniotoensis + • • Yok. Family Marginellidae. Central Japan. 48. Marginella cotamago Yok + . 49. Marginella perovulum + • . Yok. Family Volutidae. Western 50. Voluta megaspira Sow. + + Northern, Central and Japan. Family Mitridae. 51. Mitra hondana Yok. + • • 52. Mitra pirula Yok. + . Family Fasciolariidae. 53. Fusus perplexus Adams. + +.... + + + Northern, Central and Western Japan. 54. Fusus .coreanicus Smith. + + + • • Western Japan. 55. Fusus niponicus Smith. + + Central Japan (52 fathoms). Family Buccinidae. Japan. 56. Chrysodomus arthriticus + + + + + + •• Northern Val. Northern Japan. 57. Chrvsodomus schrencki . + + Yo"k. 58. Sipho obesiformis Yok. + + close to S. Kroeyeri Moll. 59. Sipho (Parasipho) nip- + (Very ponicas Yok. of the Arctic). • Northern and Central Japan. 60. Siphonalia spadicea Rve. + Japan. 61. Siphonalia trochulus Rve. + + + .. + + + Central Central to Southern Japan. 62. Siphonalia kellettii + • • Forbes. California. Northern and Central Japan. 63. Volutharpa perryi Jay. + + + + Northern to Southern Japan.| 64. Eburna japonica Rve. Art. 1.—M. Yokoyania : 'u- 9 o o LI VI NO u c3 v.