The Sambagawa and Mikabu systems are two important formations in the Japanese islands which have long been believed to reveal independent stratigraphic units among the older formations., The former consists of various crystalline schists, while green schits, or so-called "clastopyroxenite" by KOTO, are the leading members of the latter, to which several other metamorphosed rocks are found associated in one system., Because of barren of fossil the stratigraphic positions of these systems have been laid on the debatable ground., The current opinions on the moot question which have so far been established by Japanese geologists may be classified into the following three : a., The Sambagawa, Mikabu and Titibu systems are successively disposed in an order of geological age, among which the last one is the oldest fossillferous formation in Japan, and accordingly the other two below the Titibu must be pre-Carboniferous., b., The three systems are in the same order mentioned above, but they are separated from one another by two unconformities., Because each unconformity implies tremendous time-gap, the age of the Sambagawa could be as old as pre-Cambrian., c., The sambagawa and Mikabu systems are nothing but the metamorphosed Titibu system., Lately the writer made a renewed study on the sambagawa and Mikabu systems in the northeastern part of the Kwanto Mountainland where the systems are typically developed., As his results are summarized below, he came to the conclusion which is different from all of those opinions referred to above., Untiring effort of the writer for the determination of their geological agds was frustrated with the find of the fact that the two systems are in tectonic contact with the Titibu, wherever they are found together., More precisely, the Sambagawa and Mikabu systems apparently capping the Titibu in the surveyed area are in fact the Nappe of the two systems upon the Titibu., Moreover, the sambagawa system, in so far as can be seen, merges with the Mikabu and no definite boundary can be drawn between., The superposition of the Mikabu on the Sambagawa system may be a general status, but the reverse relation is met with at some places and a part of one system is in the heteropic relation to another part of the other system., Therefore the view of the two systems as independent stratigraphic units established by previous works no longer possesses raison d'etre., Furthermore, these formational names simply imply the metamorphosed facies of one or more formations., In other words, Sambagawa and Mikabu cannot stand as names of independent stratigraphic units., However, it is advisable that such classical names as Sambagawa and Mikabu are applicable to designate these kinds of metamorphosed facies, as the Ryoke metamorphics are used by the Japanese geologists in a similar way., As has been reported lately, the writer diseovered Radiolarian remains in certain parts of the Sambagawa metamorphics., Judging from these Radiolarians, it is certain that the fossiliferous rocks are Jurassic., On the other hand, it should be noted that the original rocks of the Sambagawa and Mikabu metamorphics are as a whole more allied to the assemblage of the Titibu rocks than to that of the Jurassic rocks in the Kwanto Mountainland., Bringing these evidences together, the writer led at length to the contention that both of the Jurassic and Titibu systems are comprised in the Sambagawa and Mikabu complexes, and that, if the two complexes are tied up in one, it reveals the metamorphosed facies of a series of formations ranging from Carboniferous to Jurassic., For this the writer intends to propose "Nagatoro system, " because the system bears not only a profound tectonic meaning but distinguishing petrographic characteristics, although several stratigraphc questions still remain unsolved. [the rest omitted]

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The Upper Triassic Mine and Atsu series are rspectively developed on the west and southwest sides of Akiyoshi plateau, Yamaguchi Prefecture., The Upper Palaeozoic Chichibu series of the plateau is unconformably overlain on its west side by the Mine series which is in turn generally monoclinal to the northwest except its western marginal part where the series forms a syncline and is delimited by a fault from the phyllitic rocks of Toyogatake in further west., The stratigraphic succession of the Mine series is shown in the table given below : [table] The Hirabara stage begins with the basal limestone conglomerate and consists of clay, shale, sandstone and conglomerate in alternation., A few coal seams are intercalated in its top and basal parts., The lower part of the Momonoki stage is composed of the alternation of thick conglomerate, sandstone and shale with intercalations of main coal seams ; its upper part consists in the main of thick sandstone., The Aso stage consists of the alternating beds of clay, shale, sandstone and a few coalseams in the lower part and mainly of thick massive sandstones in the upper., While the Momonoki stage overlies the Hirabara conformably or slightly para-unconformably in the southern part, the former, overlapping the latter, covers the Upper Palaeozoic Chichibu series directly in the northern part., As may be seen in the following lists, the Aso and Hirabara stages yield marine and brackish shells in various horizons, while the Momonoki contains no shells but a number of plants., FAUNA: Hirabara stage - Trigonia (Minetrigonia) hegiensis SAEKI, Halobia charlyana, Oxytoma zitteli (TELLER), Lima naumanni, Rhynchonella nasai, "Pleurophorus" sp., aff., P., perlongus, Edentula ozawai KOBAYASHI, Cardinia sp., Gervillia sp., Anodontophora sp., Syncyclonema sp., Aso stage- Pecten suzukii KOBAYASHI, Lima naumanni, Pseudomonotis sp., aff., P., spitzbergensis, Anodontophora sp., Pecten sp., Flora: Hirabara stage- Neocalamites carrerei (ZEILLER), Cladophlebis haiburnensis L., and H., Taeniopteris minensis OISHI, Cycadocarpidium swabii NATHORST, Pityophyllum longifolium (NATHORST), Podozamites lanceolatus(L., and H., ), P., schenki HEER, Nageiopsis raetica OISHI., Momonoki and Aso stages- Neocalamites carrerei (ZEILLER), Cladophlebis haiburnensis L., and H., C., nebbensis (BRONGN., ), C., raciborskii ZEILLER, Taeniopteris minensis OISHI, Pityophyllum longifolium (NATHORST), Podozamites lanceolatus (L., and H., ), P., schenki HEER, Cycadocarpidium swabii NATHORST (Momonoki stage), Ginkgoites digitata (BRONGN., ) var., huttoni SEWARD (Momonoki stage), Stenorachis elegans OISHI (Momonoki stage), Dictyophyllum japonicum YOKOYAMA (Aso stage), Nilssonia inouyei YOKOYAMA (Aso stage)., Judging from this floral assemblage the Mine flora corresponds as a whole to that of the Rhaetic of the world., On the other hand Halobia charlyana, Lima naumanni and Rhynchonella nasai which are the significant elements of the Hirabara fauna, occur commonly between the Hirabara stage and the Carnic Halobia bed in the Sakawa basin, province Tosa; Oxytoma zitteli and Trigonia (Minetrigonia) hegiensis are found commonly between the Hirabara stage and the Oxytoma bed in the Sakawa basin; the age of the latter may be Carno-Noric or Lower Noric., Among the Aso fauna, Lima naumanni is contained in the Halobia bed and Pecten suzuki in the Oxytoma bed., Pseudomonotis spitzbergensis is reported from the Carnic bed on Bear Island and the Noric bed at Spitzbergen., Further, it is a noteworthy fact in determining the age of the Aso stage that the fossiliferous sandstone of the Aso strikingly resembles a reddish micaceous sandstone at Kamosho which is located at a distance of about 15 kilometers from the fossil localities of the Aso stage, and the age of the Kamosho sandstone is decided at Noric with the find of Pseudomonotis ochotica in it. [the rest omitted]

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最近理學士橋本亙氏がフィリッピンの第三紀石灰岩から採集した資料中に興味ある2型のハイドロゾナが見出された。共にHydractinoid に入る可き内部構造を示し, 一つはCircoporaに他はEllipsactinia 及び Cyclactinia に多少類似の性質を夫々有する。前者は骨格の内部構造に不鮮明の點があり又地質學的位置が甚だ異つてゐる1ので, 假りにCircopora に入れて置いたが, 後者は疑ひもなく新屬でPhilippinactiniaなる種屬名を玄に提案しておいた。

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シュワーガーは力ール・ニコバールの鮮新層から多數の有孔蟲を記載したが其中或種類を除いては其後殆ど引用されないか或は同物異名として他の種名に移されて來た。本研究の材料は其模式産地より得たる者でシュワーガーの者のtopotypesである。シュワーガーの圖及び記載よりは稍々正確に或種を説明する事が出來る。Nodosaria fistucaは口孔の性質から今日Ellipsonodosaria fistucaと爲す可き者である。Nodosaria tosca本種に同定される者は新第三紀層に廣く産するが口孔の性質が不明で正確に其屬を決定する事が困難である。Nodosaria lepidula 之は今日 Ellipsonodosaria lepidulaと呼ぶ可き者である。Nodosaria glandigena 之も恐らく Ellipsonodosaria glandigena と稱す可き者である。Uvigerina hispida 此の記載は其名稱に適合する樣に小突起で蔽はれて居る印象を與へるが, 原圖が棘状突起を有する樣に畫かれてあるので本種に同定された者は稀であるが太平洋地域及び他地域の新第三紀層中にも廣く分布する者の樣である。Uvigerina nitidula, Uvigerina gemmaeformis は口孔の性質が不明であるが恐らく之と同種であり, 此者は瓜哇及びフィジーの新第三紀層中にも産する。Urigerina proboscidea 之は大平洋中の島嶼及び米國加州の新第三紀層中に産する。Dimorphina striata本種は今日Siphogenerina striataと稱す可き者である。Fissurina staphyllearia 本種はEntosolenia staphylleariaと呼ばる可き者である。Pleurostomella alternans從來本種に同定されて來たが其同定が正しくない者が多い。チャレンヂャ一報告に於てもブラディーがシュワーガーの原圖及び記載とは矛盾する樣な者を同定して居る。Pleurostomella brevis今日迄本種に同定された者が多々あるが正しくカール・ニコバールの者に同定し得る者は太平洋地域の現生及び新第三紀層所産の者のみである。Discorbina sacharina之はGlaborotalia menardi var., sacharina とすべき者で太平洋地域の鮮新期より現生期に亙って産出する者である。Anomarina cicatricosa之はCibicides cicatricosaと改稱す可き者である

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