地学雑誌
Online ISSN : 1884-0884
Print ISSN : 0022-135X
ISSN-L : 0022-135X
87 巻 , 6 号
選択された号の論文の7件中1~7を表示しています
  • 坂上 澄夫
    1978 年 87 巻 6 号 p. 313-329
    発行日: 1978/12/25
    公開日: 2009/11/12
    ジャーナル フリー
    I. Outline of historical reviews
    The Paleozoic bryozoan researches in Asia were introduced after the 20th century except for the reported from the Salt Range bryozoan fauna which was described by WAAGEN and PICHL (1885), and WAAGEN and WENTZEL (1886). In East Asia, although there are some pioneered works on the Paleozoic bryozoans by MANSUY (1912, 1913), YABE and HAYASAKA (1920), NEWTON (1926), REED (1927), YOH (1932), OZAKI (1933), YABE and SUGIYAMA (1942) and so on, they were not systematic studies of Bryozoa.
    The Paleozoic bryozoan studies in East Asia were earnestly made since 1950, namely, in China by YANG, Loo, Hu, HSIA, LIU, LI ; in Altai and Siberia of USSR. by NEKHOROSHEV, TRIZNA, ASTROVA, MODZALEVSKAYA, ROMANTCHUK and MOROZOVA ; in Japan and Southeast Asia by SAKAGAMI and SUGIMURA.
    II. Study of Paleozoic bryozoans in Japan
    Generally the Silurian-Devonian bryozoans in Japan are ill-preserved and rare, and only one species of the Silurian bryozoan : Monotrypella? yabei has been hitherto described by SUGIYAMA (1944) from the middle Silurian of Japan. Recently, some materials, however, were collected from the Kitakami and Hida massifs. They are Stereotoechus Kitakamiensis (n. sp., MS) and some fenestellids from the middle Devonian of the Kitakami massif, and Eridotrypella? sp. (probably n. sp., MS), Fenestella sp. indet. and Sulcoretepora sp. indet. from the Devonian of the Hida massif. They will be described paleontologically in the near future. The Carboniferous-Permian bryozoans in Japan have been summarized by SAKAGAMI (1967b, 1970a). Later, SUGIMURA and OTA (1971), SUGIMURA (1972, 1974), and SAKAGAMI and SUGIMURA (1978) studied some Upper Paleozoic bryozoans from the Akiyoshi limestone.
    III. Study of Paleozoic bryozoans in China
    Recently, its Paleozoic bryozoan studies have been greatly progressed by the efforts of YANG, K. C. and his collaborators. At present, 440 species of the Paleozoic bryozoans have been described and illustrated as shown in Table 1.
    IV. Study of Paleozoic bryozoans in Southeast Asia
    The Silurian and Devonian bryozoans from Indo-China are very poor and insufficient for comparison with those of other areas, however, the “Anthracolithic” bryozoan fauna, in spite of small one, contains the European and/or Salt Range elements. The further studies should be expected.
    On the other hand, our knowledge of the Paleozoic bryozoan fauna from the Thai-Malayan district has much progressed in this decade by SAKAGAMI (1963-). At present, about 30 species of the Carboniferous and more than 90 species of the Permian bryozoans have been described from 16 localities in the Thai-Malayan district. Generally these bryozoan faunas constitute a unique assemblage but contain both European and Asian elements among its genera.
    V. Comparison of Paleozoic bryozoan facies between Japan, China and Southeast Asia
    Table 2 shows the distributions of the bryozoan genera in East Asia. As shown in Table 3, total numbers of bryozoan genera in each Period are gradually increased to the younger, but it is different from the world-wide tendency.
    The most world-wide genera in the Paleozoic Group, i. e., Fistulipora, Fenestella and Polypora are known abundantly also in East Asia. They are known from the Ordovician to Permian, but are extremely rare in the Ordovician and Silurian. Thus, there seems to be a large change of the Paleozoic bryozoan facies between the Silurian and Devonian. On the other hand, in East Asia, the common genera between the Devonian and Carboniferous bryozoan faunas are only 8 and a considerable change between them is recognized. There are 20 common genera between the Carboniferous and Permian faunas, and their relationship between two faunas seems to be successive.
  • 武内 和彦, 仲田 栄二, 山本 博
    1978 年 87 巻 6 号 p. 330-348
    発行日: 1978/12/25
    公開日: 2009/11/12
    ジャーナル フリー
    The authors tried a phytosociological vegetation survey as a fundamental part of landscape evaluation and planning in the humid sub-tropical Izena Island located in the northern part of Okinawa, southwest Japan. It is the purpose of this paper to clarify the geographical distributions and the characters of plant communities, which are affected not only by the land potentiality but also by a lot of human interventions in the Izena Island.
    As a result of plot survey, forest and weed vegetation of the Izena Island has been divided into 9 plant communities, and 2 plant communities further Into 4 and 2 subordinate communities. That is ;
    1. Forest vegetation,
    A. Pandanus tectorius community,
    B. Thuarea involuta-Casuarina equisetifolia community,
    C. Leucaena leucocephala community,
    D. Pinus luchuensis community, a. subordinate comm. of Aristida takeoi, b. subordinate comm. of Rhodomyrtus tomentosa, c. subordinate comm. of Castanopsis sieboldii, d. typical subordinate comm.,
    E. Pittosporo-Quercetum phillyraeoidetis Suz.-TOK. et HATIYA 1951,
    a subass. of Pinus luchuensis, b. subass. of Fraxinus insularis,
    F. Ardisia sieboldii-Cinnamomum japonicum community
    2. Weed vegetation
    G. Marsilea crenata-Scirpus maritimus community,
    H. Typha domingensis community,
    I. Oxalis corniculata-Panicum repens community,
    Under the recognition of the spatial distributions of the differential species in the communities, actual vegetation map was drawn up as Fig. 3.
    Then the authors discussed on the relationship between land potentiality, especially soil potentiality, and plant communities by using vegetation map. They also discussed on the relationship between land use, including religious preservation of special areas in the Izena Island, and plant communities. They found the distributions of plant communities in the Izena Island to be characterized not only by the influences of land conditions such as soil pH but also by the great influences of human interventions such as agricultural land-use.
    Such discussions will be useful when we consider the fundamental character of the landscape complex in the humid sub-tropical islands of Japan.
  • 門村 浩, 堀 信行
    1978 年 87 巻 6 号 p. 349-367
    発行日: 1978/12/25
    公開日: 2009/11/12
    ジャーナル フリー
    The main purpose of this paper is to describe and discuss the landforms and superficial deposits characteristic of humid tropical environment, with special attention to the spatial variations corresponding to the zonal arrangement of climate and vegetation, based on the 1975/76 season field research across the forest and savanna zones of inland Cameroon from 2°N to 9°30'N. Some basic data and views used for the reconstruction of palaeoenvironment in the present-day forest zone are presented.
    In the inland plateau underlain by the Precambrian crystalline rocks and mantled with dense humid forest, the landscape consists principally of small hills 40-100 m high predominated by the convexity. Hillslopes of such hills are almost evenly covered by the colluvial deposits consisting of red to yellow ferrallitic soils and gravelly layers. The colluvial deposits contain prehistoric implements of African Middle Stone Age and younger. The wide-distribution of indurated cuirasses is also recognized in the forest zone of southern Cameroon. Under the forest environment, however, these cuirasses rarely outcrop to form ledges or cornices. Dome-shaped weathering front has been occasionally found beneath the colluvial deposits and weathering profile, but in the forest zone it never controls the slope form of the present landsurface.
    In contrast to the forested areas, in the savanna zone of the Adamaoua Plateau the landsurfaces are extensively capped with ferruginous or bauxitic cuirasses and such prominent land-forms associated with indurated cuirasses as mesa, buttes, ledges and cornices are developed in the dissected part of the plateau. In this savanna zone gullying is the most common present-day process operating upon the landsurfaces, and this process has been more or less accelerated by intensive grazing and repeated burning. Termites are most active in this zone and the large-scale mounds with a diameter of 20-30 m and a height of 3-4 m are found elsewhere.
    In the drier Sudanese savanna zone of the Bénoué Basin vegetation is much more xerophyitic than expected from annual rainfall (1, 400-1, 000 mm), and the landscape is characterized by the undulating plain with towering granitic inselbergs and buttes of Cretaceous sandstones which are fringed by pediments. The superficial deposits both of gently undulating landsurface and pediments are generally stony, and cyclic deposits are found elsewhere. The youngest ones may be the product of the last 500 years as they contain potsherds. The older deposits may be the product of the past drier environments which prevailed during the last glacial age. In this drier savanna zone, the extensively stone-paved landsurface may indicate that rain-wash is the most prevailing process under the present environment.
    As mentioned above south-north variations of landforms and superficial deposits can be observed undoubtedly. However, these observations are nothing but a first approximation. As the geology, ages, relief and some other elements of landsurface differ from one area to the other, it is difficult to make a complete comparison in a strict sence. These conditions may produce the intrazonal character of both landforms and superficial deposits. For instance, inselbergs associated with bare rock surface are distributed not only in the savanna and steppe zones but in the forested areas. Coarse-grained granitic rocks tend to form for groups and boulders both in the forest and savanna zones, though they are more common in the latter. The occurrence of these features is largely controlled by the nature of lithology of underlying rocks. Stone-lines or stony deposits on and near the present landsurface are most common in the Sudanese savanna zone, but they are also found in the southern humid areas as evidenced on the partly stripped landsurface on the south of the Sanaga River.
  • 小林 貞一
    1978 年 87 巻 6 号 p. 368-369
    発行日: 1978/12/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 木内 信蔵
    1978 年 87 巻 6 号 p. 370
    発行日: 1978/12/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 前田 四郎
    1978 年 87 巻 6 号 p. 371
    発行日: 1978/12/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 小野 有五
    1978 年 87 巻 6 号 p. Plate1-Plate2
    発行日: 1978/12/25
    公開日: 2009/11/12
    ジャーナル フリー
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