Stratigraphical and chronological works studied in some decades in Central and Eastern Europe are reviewed for the introduction of the problems concerning the subdivision of the Last Glacial. The results based upon the löss stratigraphy, the chronostratigraphy recently established in Denmark and Netherlands and the glacial sequence of the Last Glacial around the Alps are summarized in the first three sections (Fig. 1, 2, 3). The Göttweig Interstadial in its original sense (GROSS, 1958) should be abandoned, for it was defined by many different soil horizons which are now believed to be R/W Interglacial, Amersfoort, Brörup and Paudorf Interstadials. Not a few contradictions still exist among many researchers, however, the climatic curve obtained in Netherlands (Fig. 5) could be regarded as the standard succession of the Last Glacial in Central Europe. According to that, the Last Glacial of Central Europe is divided into three stadials seperated by interstadials. The Early Glacial includes two or three interstadials which might correspond to the sea level fluctuation recently obtained in Barbados Island (Fig. 4). It is hopeful that the already abandoned Woldstedt's climatic curve (WOLDSTEDT, 1958) and Gross' subdivision (GROSS, 1958) should be replaced by new references (WOLDSTEDT, 1962, 1967 and HAMMEN et al., 1967, 1971), though the old ones are still cited in Japan.
Core samples from the two boreholes were studied to clarify the sedimentary environment by diatom assemblage analysis: the results are as follows. 1. The Holocene sediments are divided into two parts, namely the sand and the silt facies (Hs Hc). It seems that they are synchronous and heterofacies to each other. The upper part of Hs-facies may be correlative with sediments during and after the small regression of Yayoi belonging to Subatlantic age. And lower and middle parts of Hs-Hc-facies may be correlative with sediments during the Jomon transgression. 2. Beneath the Holocene, the late Pleistocene sediments are developed to fill up dissected and buried valleys. The uppermost Clay (C) may be correlative with the Nanagochi formation in the Tokyo downtown area and the Nanyo formation in Nobi Plain. The sand and gravel (G-1) may be correlative with the Buried terrace gravel-1 in the Tokyo downtown area. The clay underlying the former (Mc) may be correlative with the Tachikawa Loam in South Kanto district. Carbon date of a sample from the lower part of the alternation of sand, silt and clay (Alt. s-c) shows the value of 24, 260+2, 810-2, 080y. B. P. 3. Some additional discussion on the systematic position of Coscinodiscus temperei, Cymatotheca weissflogii and Tryblioptychus cocconeiformis are made from a viewpoint of morphological features of diatom valves.
The paucity of reports on the vegetational history of the alluvial peatland overlooked the Japan Sea in Tohoku district encouraged us to study it. In this paper the pollen analytical features of the Megata peatland situated at an altitude of above 10m in Akita Prefecture are described with a view to discussion of the vegetational history in the peatland and its surroundings from 3, 500y. B.P. The results are summarized as follows. 1. The profile at the north of the peatland from which samples were taken for pollen analysis was mostly composed of autochthonous peat, of which the ages were calculated to be 3, 180±85y. B.P. (N-2003) at the 500cm depth and 2, 080±80y. B.P. (N-2004) at the 300cm depth on the basis of 14C dating. 2. Pollen diagram derived from peat profile is characterized by the occurrence of Cryptomeria, Fagus, Quercus and Alnus with a high frequency of pollen and a gradual increasing of Cryptomeria from 3, 000y.B.P. of the initial layer. In pollen diagram three pollen assemblage zones on the basis of the prosperities of these dominant genera are differentiated as follows: I) Fagus-Quercus-Alnus zone (630-420cm) II) Cryptomeria-Fagus-Quercus-Alnus zone (420-70cm) III) Pinus-Cryptomeria-Alnus zone (70-0cm) 3. The pollen diagram suggests a gradual change from the forests dominated by Fagus and Quercus, to Cryptomeria-Fagus forests now found locally in Akita Prefecture. An increasing of Pinus and Cryptomeria at the zone III seems to be influenced by plantation in the neighbourhood of the peatland.
The present paper is the first of a series to the elucidation of the vegetational history done by pollen analysis of moor sediments taken from the Chugoku district, Japan. Orogatawa moor is located in the Oroga pass at 700m above sea-level between Mt. Minagasen and Mt. Kami-Hirusen within the Chugoku Mountains, in the northern part of Okayama Prefecture. The profile of about 280cm sediments obtained from the deepest portion of the mooris divided into three layers; the lower one is silty clay, the middle one muck and the upper one terrestorial peat. As a result of pollen analysis of these samples, three major vegetational changes for the last 6, 500 years are recognized by the fossil pollen data from 29 levels as follows; 1. Quercus, Fagus, Ilex stage (280-190cm) (6, 500-4, 000y.B.P.); 2. Quercus, Fagus, Carpinus stage (190-70cm) (4, 000-1, 500y.B.P.); 3. Fagus, Quercus, Pinus stage (70-0cm) (after 1, 500y.B.P.). Quercus is the most dominant tree in the pollen diagram. The evergreen type is dominant at the lower part of the first stage. The frequency decreased gradually during the upper one of the first stage, and the second one. On the other hand the deciduous type increased during these stages, and the frequency is higher than the evergreen one at the third stage. The destructions of natural forests by human activity may have started at third stage (ca 1, 100 y.B.P.) as shown by the sharp decrease of Quercus pollen, the gradual increase of Pinus one, and the great abundance of Gramineae one. The sedimentation rate based on 14C dates in this moor is considerably great compared with some data taken from another moor in Japan. It rises gradually from the bottom to the surface as follows: 0.05cm/year (200-150cm), 0.06cm/year (150-100cm) and 0.07cm/year (50-0cm) with exception of a decrease (0.025cm/year: 100-50cm).