In Shikoku, the Median Tectonic Line running nearly from east-northeast to west-south west separates Ryoke metamorphic complex overlain by late Cretaceous Izumi group and partly with Quaternary sediments to the north from Sambagawa crystalline schist to the south. Topographical contrast is very conspicuous along this tectonic line, especially in the central part of Shikoku, where the northern rim of the Shikoku Mountains is bordered by the magnificent Ishizuchi fault scarp abruptly descending northwards to the Seto Inland Sea depression. The area along the Median Tectonic Line is a belt of high tectonic instability in the Quaternary Period.
The writer investigated the various features of active faulting and associated phenomena in this area to clarify the modes of faulting and the processes of tectonic relief occurred along the Median Tectonic Line since the Neogene, especially in the Quaternary. Active faults along the Median Tectonic Line are remarkably linear and are arranged en echelon. They generally dip northward with high-angled or nearly vertical fault planes, whereas thrust planes of the Median Tectonic Line in a narrow sense decline northward with rather low angles of 30° to 35° in the western part of Shikoku. The active fault system has been displaced predominantly in the right-lateral sense at mean rates of 5 to 10m/10³ C¹⁴ years in the late Quaternary. Active lateral faulting dates from the beginning of the Quaternary, and has repeatedly acted at approximately constant or gradually accelerated slip rates. Vertical displacement upthrown to the south has been accompanied at rates of about 0.4 to 0.8m (or more than these) /10³ C¹⁴ years, forming the Ishizuchi fault scarp. It is inferred that the vertical displacement also has acted in the similar processes to the lateral one and has amounted to about one thousand several hundreds of meters. Transcurrent buckling or wavy deformation associated with the lateral displacement is recognized in the northern down thrown blocks, judging from the topographic features and the distribution patterns of late Quaternary deposits.
Quaternary faulting of these modes along the Median Tectonic Line is quite different from its earlier history of predominantly dip-slip displacement caused by approximately northsouth shortening and has acted since the early Quaternary under the regional stress field of nearly east-west compression in Southwestern Japan.

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In the mountain valley drained by Kabura River the farmers have made great efforts to expand the acreage of growing konjac tuber since the middle of Meiji era, making this crop the predominant situation as an agricultural commodity in their farming. Accordingly, at present the valley region is one of highly specialized regions in the agriculture of Japan.
Around 1955 the farmers of Nanmoku-mura, one of the village municipalities in the valley region, had adopted an advanced cultivation method of “transplanting cultivation” in order to increase the amount of the product through putting in a great amount of labour for growing konjac per unit of area. Recently it is noticeable that the highly labour intensive cultivation, once established as transplanting cultivation, is moving towards a newer method, saving labour by using various kinds of machinery and material goods abundantly since they appreciate this as “technological innovation in konjac growing”. Though konjac growing has long been recognized as an exclusive crop on steep slope arable land found in this valley, the technological innovation permits cultivation of this crop on gentler slope land, flat land or even on rice field in the adjacent lowland regions. The farmers in the lowland regions have begun to introduce this crop to some extent so that they are now competitive to those in the mountain valley regions. In the lowland regions konjac growing has been studied in the following two points: what kind of technological innovation in konjac growing are adopted in order to stabilize the yield? Are they expecting a further expansion of its growing in the region where they can choose various crops or enterprises? These problems are to be explained by analyzing the relationship between price change of konjac product and labour productivity.
The writer studied on what kinds of technological innovation in cultivating practices are adopted and also on how much degree they have attained to a higher level of labour productivity through introduction of new techniques.
The results obtained are as follows: In the valley region the use of land resources has been reached to a highly intensive level in farming, emphasizing konjac growing from the early times. Since konjac growing was obtainable of high profitability for the farmers, they put a great deal of labour in raising the yield. For instance, they developed “transplanting method” from the older method depending on natural growth of konjac tubers. Moreover, those factors such as steepness of cultivating fields, unfavourable accessibility to the fields, and dispersion of parcels of holding due mainly to the physical conditions of the mountain region are enforcing them to demand large amount of heavy labour input for its cultivation.
The adoption of technological innovation has brought labour productivity to a higher level. To explain this, the improvement of mulching practice, construction of benyl pipes for spraying and irrigation, introduction of weed control medicines in case of fertilization and spraying, and application of small size tractors on steep fields, construction of tuber collectors and cables in case of ploughing and transportation are main items in technological innovation.
Because of its higher profitability konjac growing has gradually expanding to the lowland regions as mentioned above. Technically it depends mainly on the advancement of spraying practices which are to stabilize the yield, land improvement and adoption of Chinese variety of konjac plant. This variety is easier to cultivate in the lowland than the native one.
Thus technological innovation in konjac growing in the valley region has pushed forwards along the lines of cultivating practices-namely from labour intensive cultivation, caused by topographical limitations, to labour saving method.

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The Tama River flows from Mt. Kasatori, which rises in the southern part of the Kanto Mountains, down to Tokyo Bay. The lower reach of this river forms an alluvial plain which is known as the Tamagawa Lowland.
Recent deposits and their basal landf orm, i.e. buried landf orms in this lowland were evaluated by using some thousands of borehole records. Buried landf orms, which have vario-us geneses, were formed in the past about thirty thousands years.. In this paper, Recent de-posits denote the fills above the buried landf orms, which have been depositing in and after the main stage of the Wurm ice age.
Many geologic sections were constructed in order to examine the borehole records. Some of them are shown in Figs. 1, 2, 4, 6, 7 and 8, and their locations are shown in Fig. 5.
It is said that the difference in f acies, soil mechanic properties, contained materials and colors of deposits are useful indicators to analyze stratigraphy. On the basis of the difference in these indicators, longitudinal and transversal continuities of deposits were examined. As a result, the deposits above the basement of the Miura group (BR) were divided into Recent deposits composing buried river terraces and deltaic plains (T₁ G, T₂ G, TS and TL), diluvial Tokyo formation I (DU) and II (DL). The characteristics of indicators to identify each deposit are shown in Tab. 2.
Based on the datum geologic sections and indicators, many other borehole records were examined to discriminate Recent deposits from the others and to draw their basal landform by contour lines. On the other hand, the surface of unconformities which appear in the geologic sections, can be regarded as the buried landforms. Accordingly, the buried landforms are able to be restored by tracing the surface of unconformities.
The main results obtained in this paper are as follows:
1) Recent deposits are classified in to UA, US, UC, MS, LC and BG on the basis of lithostratigraphic units (Tab. 1). UA, US, UC and MS compose the upper part, LC and. BG compose the lower part. It is common in other coastal lowlands in Japan that Recent deposits consist of two parts. But it could not be made clear in, the Tamagawa Lowland whether the upper part was lying unconf ormably on the lower part as in the Tokyo Lowland or not.
2) The basal landform of Recent deposits was analyzed as shown in Fig. 5 by contour lines. The buried landforms which are shown in Fig. 9, can be classified into three types, i, e. buried river terraces and deltaic plains, buried valleys and buried coastal terraces.
Buried river terraces and deltaic plains: Tachikawa terrace which is covered by Tachikawa loam, the uppermost part of the Kanto volcanic ashes, is buried under the alluvial plain about two kilometers upstream from the location of section line A-A' (Fig. 5). This buried Tachikawa terrace is divided into two parts-T₁ and T₂ (Fig. 9). If we extend T₁ downstream, we can find deltaic plain T_s which are 10-20 meters below sea level. T_s is composed of sandy deposits (TS) with distribution restricted within the lower reach of T₁ and on DU.
It cannot be directly seen if T₁ continues to T_S, since T₂ and the palaeo Nomi River separate them. But the longitudinal section (Fig. 6) and distribution of T_s suggest that it is appropriate to regard T_s as the deltaic area of T₁. Considering that the lower part of the Tachikawa loam had fallen about 25, 000 years B. P., we might regard TS and the upper part of DU in the Tamagawa Lowland as the deposits which were formed during the Wurm interstadial around 30, 000 years B. P..

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