The delta plains in Japan were reclaimed to a large extent since the end of the middle ages when the techniques for public works were remarkably improved in relation to the progress of fortification. In those days, reclama-tion work for a delta plain was generally carried forward from the inland part to the sea-shore. But in the case of the Kakogawa delta, Hyogo Prefe-cture, the portion on the left bank of the river (eastern half of the delta) was first reclaimed into paddy-fields in the Nara Period (ca. 700-800), but the western half was left unreclaimed, even at the end of the middle ages, left as a waste land devastated by the frequent shifting of the river course and the repeased invasion of the sea. Thus, the Kakogawa delta plain gives an exceptional example as to the process of reclamation of a delta plain. The reason why the estern half of the delta plain was at first reclaimed is supposed to be explained as follows. The Kakogawa delta plain is situated in the west of the Rokko block mountain which recently uplifted. So the eastern half of delta, lying nearer to the mountain was much more affected by the block movement than the western half was, that is to say, the delta was tilted from the east to the west. As a result, the main course of the Kakogawa was probably made to shift gradually from the east to. a distributary in the west. But the existence of the island-like submerged mountains, made up of quartz trachyte, dominating above the western half of the delta plain, which had acted as the obstacle to the flow of the western distributaries, now made the reinforced' stream run more wildly than before. Consequently, the recla-mation work and the river improvement in the western half of the Kakogawa delta became more difficult than before. Thus the western half was left unre-claimed even after the eastern half had been brought under cultivation. Yet, since the end of the middle ages, what with the development of pulbic works techniques and what with the good administation of the successive lords of Himeji, improvement of the river courses, construction of the sea dyke were carried out, and reclamation work was remarkably progressed in a short period.

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(1) In the Oki islands under feudal systel-11, the principal products were of the self-sup porting agriculture based on rice-fields and pastures (called Makihata), and the ma rine and the forest products were only subsidiary. (2) Accordingly, the village societies in the islands were remarkably characterizedd by the medieval and feudalistic system, and there also existed a village co-mmunity. (3) Owing to the isolated. and blockaded system of economy, emergency funds were considerably well provided. (4) The traffic by saili-ng-ships was opened in the middle of the Tokugawa period, (1603_??_1867) and it made the islands easy to participate in economy of the mainland. (5) Oki was regarded as an important port of call for the sailing-ships on the westward route since the tinge of, Genroku, (1688_??_1703) and became a repre-sentative one in the Japan Sea during the time of Bunka (1815_??_1817) and Bunsei (1818_??_1829). (6) Owing to the development of the shipping business, some products of Oki were made into merchandise. An tong them dried ear-shell, boild trepan and dried cuttlefish were produced in a great quantity, as they were then the principal exports for China through the official Lands of the Shogunate Govern cent. (7) Woods, cows and horses were also transported out from the islands. (8) Ti he village masters of the coastal villages acted as a wholesale dealer, and became incipient commercial capitalists. Saigo, where the greatest harbour in Oki was located, grew into a commercial town. (9) The wholesale dealers also managed the sailing-ships and owned the seines, and grad L.ally turned to be absentees both by practising usury and possesing lands as capitalist. (10) Between the indepedent farmers and the commercial capitalists, some interest came forth to trouble each other. (11) “The Oki Riot”, as it is called, was an peasant's uprising based on the opposition between tike peasants and the commercial capitalists. (12) The commerciall capitalists tried to menage the business of a company in Oki, but they were defeated by the far greater and stronger capitalists o the main-land. (13) Time poor resouces of the islands both in qaulity and quantity made Oki to be an isolated islands in a new sense in the course of the development of modern capitalism.

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In recent years we have shad many studies on the hierarchy of central places, or the relationships between towns and their surrounding areas. The writer researched the local passenger traffic for a n-teasurement of actual interaction, and some guantitave data on origin, destination, route and dire-ction of traffic flows. By analysis of these data, he could see results as follows:
1) The relationships betw ween. regional centers and their umlands can bee down. by the following formula; Y=aX-b where Y=frequency of convergence, on the center, X=distanee from the center to each hamlet in the ummhland. a=the ideal frequency of trips to the center in the community, and b=afigure that expresses the relation between frequency of convergence upon. and distance to the central place.
2) It can be said regarding the formula in general. that the larger the. center, the smaller the value of b. But in the case of the isolated center, some of the smaller ones have more spacious unhands and their values of b. are very small. So We may have to pay attention too not only the population of centers, but also to their locational pattern, in deciding the hierarchy of central places.
3) In the Japanese country where no railway is available, the average person covers trim of a distance of 2_??_2.5km on foot. In the case of tripe of about 3km or more, they commonly use the bicycle or bus. The bicycle is predominantly used for traveling distances of 3_??_7km; the bus prevai-lling for the ones of more 8km.
4) There are the following relationships between two neighbouring centers. a) If the one has a population less than 1.5 tunes as many as the other, these two traffic communities are in the same class. b) If the one is 1.6_??_3.7 times more largely populated than the other, the traffic community of the-former belongs to a higher class than does the latter. c) If the population is 7 times or more greater, the larger traffic community includes the smaller-one, and the cities are both part of the same traffic community.

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The mountains of the upper drainage area of the Watarase have been wasted remarkably as a result of the destruction of the forest by smelter fumes of the Ashio Copper Mine, so that the bare land has become widely distributed there. This wasted land has greatly influeced flooding in the Watarase drainage area.
Making clear the present conditions of the wasted land and the relationship between the supply of debris front bare land slopes and the sediments on the river bed from. the view point of the Watarase flood control is most urgent problem.
There is considerable literature on the historical studies and on the. reclamation of the vegetal cover of, the wasted land but little work has been done in analysis of the present conditions of the, debris size distribution on the bare land slopes or the influences on the river bed deposits.
The purpose of the present study is to determine how the debris size, distribution on the “tall” is controlled by th rock properties and what-relationship exists between the supply of debris from. the bare land slopes and the sediments in the river bed. Also this paper reports the results of measurement of the transported materials, and their solution, suspension, and saltation in the river.
The general conclusion of this study are as follows:
1) The debris size distribution on the bare land slopes has been controlled. by the rock properties. For example, the debris of qurtzporphry has many boulders and gravels of 250 -64 mrn in diameter with few fine material (Fig. 5-1). The debris of liparite has few boulder and comparatively much gravel of 128mm diameter, size and, much fine material (Fig. 5, -2). The. frequency distribution of granitic debris shows many gravel particles of 32-8mm diameter, size and shows many gravel particles of 150mm in diameter with much fine mateial. That is. to say, the distribution has two peaks (Fig. 5-3). Finally, the debris, of Palaeozoic sandstone has many boulders and. that. of Palaeozoic shale has much fine material (Fig. 5-4).
The facts above mentioned indicate the unit of debris size derived from the-different rock beds and determine the debris size distributions before the river-bed deposition. These determinations are important in the investigations of river bed sediments.
2) There are many “tali” below the bare land: slopes. Flood waters tra-nsport this talus rock debris to downstream locations where the consequent deposition increases lower course flooding.
3) Where the supply of debris. from the mountain side to the river bed is considerable, the mountain river bed shows sediments like mud flow deposits.
4) The particle sizes in the wasted land river bed portion are generally, smaller than those in river bed portion where the drainage area is vegetati-on-covered.
5) The amount of solution on the rivers of the wasted land is extremely small but the amount in suspension is very large.

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