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Volume 35, Issue 1
Displaying 1-6 of 6 articles from this issue
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III. Ribs, scapula and os coxaeNorihisa INUZUKAArticle type: Article
1981 Volume 35 Issue 1 Pages 1-18f
Published: January 25, 1981
Released on J-STAGE: July 26, 2017
JOURNAL OPEN ACCESSThe ribs, scapula and os coxae of Desmostylus mirabilis NAGAO from Keton are described. Desmostylus appears to have 13 pairs of ribs (INUZUKA, 1980a), of which are characteristic the following features: The eighth rib the longest; the seventh the largest in curvature; costal head long medio-laterally in the anterior ones, but the largest and long foreand-aft in the middle ones; neck longest in the eighth or ninth; costal tubercle present until the twelfth; dorsal muscle area well developed in the fifth to the ninth, inclined more stronger in the more anterior ones; shaft not fiat in cross section except for the anterior ones; thorax nearly circular in cross section. Scapula long, triangular in outline; facies serrata not so rough; posterior border thick; scapular spine located at a little forward to the middle, being relatively high, not so inclined; acromion terminated at a level higher than that of the glenoid cavity; tuber spinae well developed; glenoid cavity relatively large. As to the os coxae the following characteristics are recognized: Wing of ilium not so expanded laterally; ischium well developed, making a wide ischiatic plate; pubis projected downward to horizontally and slightly backward; obturator foramen faced rather laterally than ventrally because of wide symphysis; acetabulum located at the mid-length, facing out and backward; pelvic symphysis long; sacro-iliac angle large, being about 150°.View full abstractDownload PDF (3324K) -
Makoto KATO, Sumio KUMANO, Shomei OKADAArticle type: Article
1981 Volume 35 Issue 1 Pages 19-25
Published: January 25, 1981
Released on J-STAGE: July 26, 2017
JOURNAL OPEN ACCESSThe search for whale bones at a cliff in Tenneru, near Kushiro, Hokkaido revealed a new occurence of Fortipecten takahashii from the lower part of the "Kushiro Group " developed there. The " Kushiro Group " in Tenneru is divisible into two units by an unconformity in between, and is also unconformably overlain by the Kutcharo pyroclastic flow deposits of about 29,400 y.B.P. The upper part of the "Kushiro Group" in Tenneru contains "Tenneru shell bed" and is considered here to be Tyrrhenian deposits. Fortipecten and some other associated molluscs were found from the lower part of the lower unit of the "Kushiro Group". At least the Fortipecten horizon is correlatable with the other Pliocene strata in Hokkaido. The "Kushiro Group" as a whole has long been considered as representing the marine, older Diluvial deposits in Hokkaido, however, it now badly needs restudy as to its faunal as well as lithological succession and correlation.View full abstractDownload PDF (2354K) -
Kobiwako Research GroupArticle type: Article
1981 Volume 35 Issue 1 Pages 26-40
Published: January 25, 1981
Released on J-STAGE: July 26, 2017
JOURNAL OPEN ACCESSThe Kobiwako Research Group has made a stratigraphic investigation of the PlioPleistocene Kobiwako Group distributed in the Konan Hills, lying in the southward of Lake Biwa, for the purpose of clarifying the stratigraphic relationships between Minakuchi Hills (Kobiwako Research Group, 1977) and Katata Hills (HAYASHI, 1974). The results of the investigation as to the SetaIshibe area, the eastern part of Konan Hills, are firstly reported in this papar. They are summarized as follows: 1. The Kobiwako Group in this area, having thickness of more than 180 meters, is divided into three Members, namely the Arahari alternations, Asagarano sands and Seta gravels, in the ascending order. Among more than 18 volcanic ash layers found in these members, 13 are available as key beds. They are named Sato, Naritani I and II, Arahari I, II and III, Kiryu I and II, Asagarano, Minogo, Gokenjaya, Shimotoyama I and II, Maruoshinden, Kasayama and Sakuragaoka volcanic ash layers, in the ascending order. 2. Mineralogical analyses and paleomagnetic measurements of the volcanic ash layers found in this area are shown in Table 1, 2 and Fig. 5-a, b. It is remarkable that the normal polarity interval, which is correlative to the Olduvai Event, is found in the horizon between Kiryu I anp Minogo volcanic ash layers. 3. Some plant megafossils collected from the lower and middle horizons of this area are the elements of the Metasequoia flora. On the other hand, the elements of flora showing the Quaternary cold climate are found in the upper horizons of the Kobiwako Group in this area. The floral change can be found in the horizons near Maruoshinden volcanic ash layer. 4. The Kobiwako Group in this area generally abuts to the basements and dips to the north or northwest gently. There are found no remarkable geologic structures except few places; in the east of Ono and near Mikumo are found flexures and faults. 5. Gokenjaya volcanic ash layer is lithologically similar to Gamodo volcanic ash layer found in Minakuchi Hills. Horizons directing to the Quaternary cold climate can coincide with the uppermost horizons of the Minakuchi Hills. Based on these and other studies, the lower half of the Kobiwako Group distributed in this area can be correlated to the upper half of the Group in Minakuchi Hills.View full abstractDownload PDF (1926K) -
Takeshi UEMURA, Yuji YOKOTAArticle type: Article
1981 Volume 35 Issue 1 Pages 41-48
Published: January 25, 1981
Released on J-STAGE: July 26, 2017
JOURNAL OPEN ACCESSThe early Jurassic Kuruma group distributed in the northeastern corner of southwest Japan was studied from the view-point of deformation facies. Several types of minor structures formed at different ductilities are developed within a syncline in Odokoro-gawa area. A mode of arrangement of deformation zones, which are defined by assemblages of minor structures, shows that the deformation grade represented by mean ductility is higher at the axial part of syncline than at the limbs. A model of tilted block movement with lateral compression by thrusting of the basement is proposed to explain such a situation of deformation facies from the examination of factors controlling the mean ductioity as an index of deformative environment in relation to the folding process of the Kuruma group.View full abstractDownload PDF (786K) -
Tadashi NISHIKAWAArticle type: Article
1981 Volume 35 Issue 1 Pages 49-52
Published: January 25, 1981
Released on J-STAGE: July 26, 2017
JOURNAL OPEN ACCESSDownload PDF (568K) -
Mizuo AIBA, Mitsuo SAYAMAArticle type: Article
1981 Volume 35 Issue 1 Pages 53-55
Published: January 25, 1981
Released on J-STAGE: July 26, 2017
JOURNAL OPEN ACCESSDownload PDF (333K)
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