To the south of the Hida Mountains, so-called Northern Alps of Japan, there extends the Hida-Mino Highland, where the Kiso and Hida Rivers drain, The highland is bordered by the Kiso Mountains, so-called Central Alps, at its eastern margin and abruptly descends from the Mikawa Highland in its southern margin.
The Hida-Mino Highland is subdivided from northeast to southwest into the Adera, Futatsumori-san and Kengyo-san blocks by the Adera and Ako fault scarps (Fig. 1). Geomorphic surfaces were distinguished in three levels in each block. In the Kengyo-san Block these surfaces are 700-900, 350-700 and 250-500 meters high, and in the Futatsumori-san Block 800-1, 000, 600± and 300-400 meters high, while in the Adera Block Block the higher ones are 1, 400-1, 700 meters high and the middle and lower ones could not be clearly classified, ranging in the height between 900-1, 200 meters (Fig. 3). The higher surfaces are represented by flat summits of the mountains in every block, and the middle ones are gently declining foot-slopes of these mountains and the lower ones depositional surfaces, composed of the Toki Gravel Beds. These geomorphic surfaces of three levels are respectively correlated among three blocks, judging from sand and gravel beds that have taken part into their formation (Fig. 5 and 7).
According to the results of the correlation of the geomorphic surfaces and further analyses of geomorphic and geologic evidences, the author concluded on the geomorphic history of the Hida-Mino Highland as follows. After the formation of the geomorphic surfaces of the higher and middle levels, the Adera Block bordered by the Adera fault scarp was uplifted, tilting northeast, and the Hida-Mino Highland was differentiated into two blocks. In consequence of dissection of the Adera fault scarp and its back slope, the Toki Gravel Beds were deposited in depressions located downstream of the Adera Block.
The southern part of the Hida-Mind Highland was further differentiated into two blocks by the Ako fault. While the northeastern block, that is, the Futatsumori-san Block, was warped down southwards, forming the Boa Basin bordered by the Byobu-san Fault Scarp along its southern margins the southwestern block, namely Kengyo-san Block, was tilted to southwest after the deposition of the lower horizons of the Toki Gravel Beds, and was uplifted about 100 meters higher than the Ena Basin. The Kiso River consequently has cut an antecedent valley into the block.
The Hida-Mino Highland gently descends to the Nobi Plain at its western margin. There are several terraces and erosion surfaces along the margin of the highland. The geomorphic relation of these surfaces to ones in the Hida-Mino Highland was discussed in this paper, too.

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1) The aim of this study is to investigate the relations between the “public investment” and the regional economy which is remarkably changing, being influenced by the “high-pitched growth” of our national economy since the middle of 1950. Aichi Irrigation System Plan is one of the good examples of these public investments on the development of regional economies undertaken by our government under the law for the “All-round National Land Planning”. Aichi Irrigation System covers about 30, 000 ha. of farm land near Chûkyô Industrial District. The industrial production of this District has come to occupy a larger part of the whole national production than ever, and with the construction of combinats at the southern part of Nagoya city, the District holds more heavy-and-chemical industry than ever. As the result of this process, the industry will have an enormous demand for water and will expect Aichi Irrigation System to supply it. But the main function of the System is to contribute to the agricultural production of this area, as far as written on the paper plan.
2) In the agricultural district covered by the Irrigation System, most agricultural families own only 0.5_??_1.0 ha. of farm each.
The farmers endeavored to increase their products for several years after World War II, when Japan suffered from food shortage and the prices of food were very high. And they supported the plan of the Irrigation System.
But since Korean Incident, Japanese industry has been quickly reconstructed, and labor market has begun to spread. Since 1955-56, the cutflow of laber forces from agriculture has remarkably increased. In 1950, most farmers' families followed only agriculture in almost all the communities covered by Aichi Irrigation System. But in 1960, as the result of the outflow of labor forces especially from the farmers' families of smaller-scale management, the ratio of the families that take their farming for a side work became to correspond to the average scales of farming managements in each community.
On the other hand, food trade was decontrolled (except rice) in 1952, and the demand for food was increased and became various. Then agricultural managements were considerably commercialized. In the Irrigaticn District, too, many farmers, above all, farmers of larger-scale management, have come to raise fruits and vegetables for the market of Nagoya and other cities.
The growth of Chûkyô industry has not only promoted the outflow of labor forces from agriculture but has urbanized the Irrigation District itself. And the communities such as Ôdaka, Arimatsu, Idaka and Narumi were excluded from the Irrigation System. Such exclusions may spread over other communities.
3) The farmers who have their farm in the Irrigation District must pay their allotment (about 400-800 thousand yen per ha.) to the government for the cost of the construction of the System. Can they make the payment as an effective investment for their farming business ? Anb can they keep labor forces necessary for the irrigating work ?
By means of the Irrigation System the paddy field can be improved so as to make it easy for the farmers to use cultivating machines and reduce the labor hours. For the families that have less than 0.7 ha., however, it is almost impossible to buy the machines, and as the increase of crops per ha. cannot be expected so much by this improvement, the Irrigation System brings them only higher producing cost of rice. Some of them must give up their farms when they are compelled to pay the allotment. And such families are the majority in this District.
Most families who have over 0.7 ha. will utilize the reduced labor for the non-agricultural work. Some families of larger scale management, probably those who have more than 1.5 ha. may utilize the reduced labor for raising fruits, vegetables and other crops.

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