Size characteristics of river bed materials has been studied by many researchers as a key to reveal the fluvial transportation processes, but their chief interests have been concen trated in how the grain size of bed materials be related to tractive force in fluvial transpor tation or to movement of grains in hydraulic conditions forming size characteristics. Be side such fluvial processes, however, we must consider the characteristics of materials them selves supplied to river bed, such as the mode of decomposition of rocks during fluvial trans portation and the grain size of rock-forming minerals of source rocks in the dranage basin. It has not been interpreted how the grain size distributions of river bed materials be related to fluvial processes or to source rock characteristics. For this reason, the authors made clear the grain size distributions of the Yahagi River bed materials and surveyed the lithol logical compositions of gravel and sand (mineral particle) in each size class, and analysed the grain size distributions of rock-forming minerals and weathered materials of granitic rocks which are widely distributed in the dranage basin of the Yahagi. The paper on the hydraulic interpretations of bedforms and size characteristics of this river is in prepara tion by the authors.
Fig. 1 shows the bedforms of this river and the analysed points of them, and Fig. 2 the longitudinal profile of the river. The profile is strongly affected by artificial construc tions such as fresh water dams. Bed materials are analysed in the field on coarser gravels and in laboratory on finer sands by the sieves of 1 /4 phi interval. Total weights of analysed materials are more than 100 kg to obtain precise features of their size characteristics.
Table 1 is the results of analyses (cummulative frequency) and Fig. 3 shows the histograms to represent the size frequency distribution. The histograms of the points No. 1 and 2 have three peaks showing tri-modal distribution and the coarsest peak of No. 1 is larger than No. 2. Finer two peaks lie at about -2_??_-l phi and near 0 phi. The histogram of No. 3 has large peak around -2 phi and becomes inconspicuous in the coarsest peak around -6_??_-5 phi. The peaks around 0 phi are perceptible in No. 1 and 2, but in No. 3. It is very interesting that almost all histograms have two peaks around -2 and 0 phi. The histograms showing uni-modal distribution also represent “shoulder” around -2 phi. This is striking characteristic of the Yahagi River bed materials. In other rivers such as the Kinu . (Inokuchi and Mezaki, 1974) and the Nagara River (Moriyama and Kambe, 1978), the bed materials shows, in general, bi-modal distribution having gravel peak (coarser than -4 phi) and sand peak (finer than 1 phi), and the size range around -2_??_0 phi represents wide “valley” in histogram, showing relative defliciencies of grains.
From the view point that the sediments are composed of some normally distributed component populations (Inokuchi and Mezaki, 1974), the authors separated quantitatively some component populations from the plots on normal probability graph paper. The bed materials of this river are composed of two or five component populations (Table 2 and Fig. 4). Although the coarser A and A'-populations will be discussed in next paper in reference to their hydraulic conditions, it is clear that the coarsest A-populations (in No. 1, 2 and 3) show downstream reduction in grain size and in mixing proportions.

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The purposes of this study are to clarify the regional and seasonal characteristics of cold frontal precipitation in Japan, and to understand the orographic controls on the precipitation and other meteorological elements during the passage of a cold front. Cold fronts occur repeatedly and compose weather patterns. Therefore, the analyses of cold frontal precipitation are also included in the synoptic climatology dealing with the accumulation of daily weather phenomena. Besides, in the region facing the Japan Sea the annual total amount of cold frontal precipitation is regarded as the second greatest, next to the precipitation due to winter monsoon. Consequently, it is necessary to research climatologically cold fronts, when the precipitation characteristics of Japan are discussed from the synoptic climatological point of view.
In this study the passage of a cold front has been defined as “the change of wind direction from southwest to northwest” and the precipitation from the cloud bands along the shear line has been discriminated as cold frontal precipitation. By means of the surface weather maps every 3 hours and the daily original registers of meteorological observation, the cause of each rainfall has been probed at the 140 stations all over Japan with the determination of the starting and finishing times of the cold frontal precipitation and the calculation of the amount of the precipitation.
Because cold frontal activity is an aspect of the heat exchange between high and low latitudes, its basic characteristics should be determined by the masses on both sides of the cold front, namely the cold air mass on the north and the warm air mass on the south, which affect the features of cold frontal precipitation to a considerable degree. Then, just before entering the Japanese Islands, the cold fronts have been classified on the basis of the equivalent potential temperature (θe) on the 850 mb level of the cold or warm air masses (Fig. 3). For the index stations Vladivostok in the cold air mass and Hachijojima in the warm air mass have been chosen, but in the case when a front passes through Northern Japan, Ust'Tyrma in the former and Hachinohe in the latter have been adopted (Fig. 2). The air masses have been divided into polar air mass (P), middle-latitude air mass (M), and tropical air mass (T) (Fig. 3). Then, the front belongs to the category of winter when the cold air mass is P and the warm air mass is M; it belongs to that of spring or autumn when both air masses are M ; and it belongs to that of summer when the former is M and the latter js T. From the cold fronts that passed over Japan for 6 years (1973 1978) 10 cases in each season, 40 cases in all, have been chosen. The dates and Be of the cold or warm air masses in the respective cases have been arranged in Table 1.
The criteria adopted when the objects of this study were chosen are as follows: 1. The cold front has been analyzed on the surface weather map drawn by the Forecast Department of the Meteorological Agency. 2. When the cold front passes, the wind change can be clearly observed. 3. At any station the cold frontal precipitation is 5mm or more. 4. The cold front passes without stopping. 5. There is no wave cyclone on the cold front before its passage over Japan. 6. The cold front is not a part of coupled cyclone.
The occurrence frequency of the cold frontal precipitation, which is 0mm or more and 5mm or more, has been illustrated in two figures (Figs. 4-a, b).

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Après la deuxième guerre mondiale, une tendance de la géographie francaise a été 1' étude sur les rapports villes-campagnes, par lesquels on a tenté de comprendre la structure régionale. On peut citer quelques Thèses d'Etat, par exemple, Campagnes et villes de la Côte d'Azur (Kayser, B.), Villes et campagnes en Bas-Languedoc (Dugrand, R.) et Les campagnes toulousainnes (Brunet, R.).
Cependant, l' étude sur les rapports villes-campagnes au Japon a été beaucoup influencé par la géographic américaine on allemande. Pour cette raison, géographes japonais ont préféré le point de vue urbain au point de vue rural. Mais, l'auteur a surtout analysé le point de vue rural. Quant au étude sur les rapports villes-campagnes par géographes japonais, on pent classer deux domaines, c'est-à-dire, l' etude sur la naissance de la ville dans la région rurale et les rapports villes-campagnes.
Or, 1'étude sur les rapports villes-campagnes offre une méthode d'etude pour expliquer la structure régionale. On peut citer par exemple les études d'Aoki, N., Birukawa, Sh., Hashimoto, S., Usui, T. et Yamada, M., Au sujet de la naissance de la ville dans la région rurale japonaise, ii existe Jyoka-machi (ville du château japonais), Shukuba-machi (ville du relais), Ichiba-machi (ville de la foire), Monzen-machi (yule religieuse) et ville industrielle. L'auteur a analysé la ville de la foire et la ville industrielle. Parce que l'essence des rapports villes-campagnes se trouve au contrôle rural par des capitaux urbains.
Alors que l'on comprend la dominance des capitaux urbains dans la formation régionale, it est très difficile de l'éprouver par les données existantes. Ii y a quelques études sur ce problème, par exemple, les études d'Aoki, N., Nozawa, H., Ohdake, Y., Sasaki, H., Takahashi, N., Takano, F. et Terasaka, A.. On ne trouve que très rarement d'étude sur les rapports villes-campagnes qui a été fait au pays etrangers par géographes japonais. On en peut citer les études de Masai, Y., Ohdake, Y. et Takagi, H..

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It is one of the essential climatological investigations to classify temperature fields spatially continued at the surface, i. e., to set up climatic boundaries in the fields. In many investigations isothermal maps drawn from sample means have been practically used to set up boundaries in the fields. There is a possibility that the isothermal maps are different from one sample to another which are even taken under the same conditions, respectively. Therefore, classification of temperature fields might be different from one sample to another. In this investigation the author classified winter temperature fields in Kanto Plain, central Japan, using inferential statistical methods. The study area is divided into units of regular triangles. Each apex of the triangles corresponds to a point at which temperature is analysed. Sample means of temperature at three points of each unit are tested one another by F and “student-t” tests to examine whether population mean values of temperature at the points are significantly different one another.
Then two areas are set up. One is continuous area which is a unit of population mean values at the points being not significantly different one another. The other is discontinuous area which is a unit of more than a pair of the population mean values being significantly different one another. Temperatures in discontinuous area, therefore, are different for different places. From the results of the tests, each unit is identified with continuous or discontinuous area. Triangle sides between continuous and discontinuous areas are here regarded as climatic boundaries.
Above-mentioned method of classifying surface temperature fields was applied to winter temperatures (daily maximum, minimum and range of temperature) in the plain. Data of temperature were taken for the winters (December, January and February) from 1961 to 1964 at seventy-eight observation stations distributed at almost equal distances in the plain. The study area was divided into units as shown in Fig. 2. Based on the comparative examination in synoptic climatological investigations (Hohgetsu, 1978, 1979), the criterion of the surface pressure patterns in the Far East (Yoshino and Kai, 1974) was adopted here as the conditions under which samples were taken. The author analysed surface temperature fields of winter monsoon, troughs and migratory high patterns of the criterion, referring to relative occurrence frequencies of the patterns (Table 1).
As far as maximum temperature is concerned, boundaries between continuous and discontinuous areas appear in the marginal parts of the plain, and continuous areas occupy broadly the middle parts of the plain. Regarding minimum and range of temperature, distribution of continuous areas under each pressure pattern are shown in Figs. 3 and 4.

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