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岩手県東磐井郡東山町南磐井里付近の上部デボン系と最下部石炭系(そのI) (北上山地西南縁のデボン-石炭両系の境界に関する研究 I.)

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Title: 岩手県東磐井郡東山町南磐井里付近の上部デボン系と最下部石炭系(そのI) (北上山地西南縁のデボン-石炭両系の境界に関する研究 I.)
Authors: 橘, 行一
Authors (alternative): Tachibana, K.
Issue Date: 20-May-1964
Citation: 長崎大学教養部紀要. 自然科学. 1964, 4, p.31-43
Abstract: The Upper Devonian (Tobigamori) and lowest Carboniferous (Karaumedate) formations are well exposed near the village of Minamiiwairi, especially along the Sarusawa river and on the slope of the southern hill of this river. The Devonian-Carboniferous boundary is observed at five places or more. One of them is shown in the Plate 1 and Fig. 3 of the Japanese text. In this outcrop the sandy rocks often intercalated volcanic materials, conglomerates and slates of the lowest Carboniferous is directly in contact with the black to gray slate of the Upper Devonian. In the crinoid sandstone at about 45cm above this boundary, Rhipidomella mitchellini var. is contained, being not found in the Upper Devonian of this district. On the other hand, Cyrtospirifcr yabei and Bellerophon are found in the slate at about 10cm below this boundary. As for as this outcrop is concerned, the relation between two systems is apparently appeared to be conformable. But these two are on the whole in unconformable relation in the Minamiiwairi district. The details of this study will be published in the next paper. In this paper, new genera of brachiopods contained in this boundary section are also described in Japanese, being summarized as follows. Globispirifer nagasakensis (TACHIBANA), n. gen. Globispirifer is abundantly found in the lowest Carboniferous of the Higashiyama district. Shell of small to large size; subcircular in outline; surface smooth in pedicle valve, but broadly plicated in brachial; obscure sulcus and low fold; delthyrium not covered by deltium; pedicle interior with developed dental lamellae; brachial with median ridge. Globispirifer is distinguished from other spiriferids in having the smooth pedicle valve with the obscure sulcus and the broadly plicated brachial valve. But in some specimens, somewhat indistinct median fold and weak lateral plicae near the anterior part are observed in the pedicle valve. Type species: Spirifer (Martiniopsis ?) nagasakensis TACHIBANA. (TACHIBANA, 1956, p.13-14, Pl.1, Fig.15-20). Nodella pexa TACHIBANA, n. gen. et. sp. This genus is mainly found in the Upper Devonian Tobigamori, but rarely in the lowest Carboniferous Karaumaedate. Shell small to medium size; pedicle valve evenly to moderately convex; brachial valve nearly to gently concave; median sulcus and fold obscure; surface of both valves marked by numerous, often quincuncially arranged spine ridges which become finer on the adult stages; spines innumerable, delicate, long, hair-like; surface also marked by growth lines; interior of brachial valve with bilobed cardinal process divided by median sulcus; teeth, sockets, alveolus and interarea absent; lateral ridges parallel to hinge line; median septum very narrow; adductors obscure ; brachial ridges not observed. Nodella resembles Sentosia in external form, but differs in the less prominent concentric markings and in having long hair-like spines. It is diiferent from Hamlingella belonging to Productellidae in its internal characters of the brachial valve and in having often quincuncially arranged short spine ridges. Nodella includes Productella nummularis WINCHELL from the English River Grits of the Mississippian and Waagenoconcha nummularis (WINCHELL) from the Upper Devonian Sulcifer beds of Kazakhstan. Type species: Krotovia nummularis (WINCHELL), (TACHIBANA, 1953, pl. 1, Figs.1-10). Iwaispirifer striatolamellosus TACHIBANA, n. gen. et sp. (Fig.4. a-c) This species is found in the Upper Devonian Tobigamori, being accompanied with Crytospirifer yabei and Leptophloeum australe. Shell small size; wider than long; cardinal extremities often mucronate; plicae simple; sulcus and fold non-plicated; often sulcus with a median plica; surface lamellose and marked by fine radial striae; dental lamellae short, frequently joined medially by secondary apical callosity; no median septum in pedicle interior; brachial interior with thin median septum. Iwaispinfer resembls Eleutherokomma, but differs from it in lacking the concentric micro-striae and micro-spines. It differs from Mucrospirifer in having radial striae on the surface of the valve. Type species: Iwaispirifer striatolamellosus TACHIBANA.
URI: http://hdl.handle.net/10069/16431
ISSN: 02871319
Type: Departmental Bulletin Paper
Text Version: publisher
Appears in Collections:Volume 4

Citable URI : http://hdl.handle.net/10069/16431

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