The Median Tectonic Line is one of the most spectacular features in physiography of Southwest Japan, ; and lies as a boundary between the Upper Cretaceous Izumi group of the Inner Zone and the Palaeozoic crystalline schist of the Outer Zone. It trends continuously and almost straight in ENE direction, especially in the middle and western part.
The writer investigated mainly fault topography and geology along the Median Tectonic Line in the lower drainage basin of the Yoshino. The results are briefly summarized as follows.
(1) There are several faults which run parallel or en echelon along the so-called Median Line. All of these faults are not necessarily active, but have been dislocated in the rightlateral sense. The witer, therefore, named these faults the Median Tectonic Line fault system. In areas intervening between neighbouring two strands of these faults, several NE-trending faults of dip-slip type develop as shown in Fig. 1&2.
(2) At Awa-Ikeda, horizontal and vertical displacements along the Ikeda fault amount to about 200 meters or more and 40-50 meters, respectively, during the past 30, 000 years (Okada, 1968). At Ikenoura, Mima-Town (Fig. 4), horizontal displacement along the Mino fault is 200-230 meters during about 25, 000 years. At Kami-kirai, Ichiba-Town (Fig. 8), hori-zontal and vertical displacements along the Chichio fault are 50 meters and 5-6 meters, re-spectively, in the recent 10, 000 years. From these data, the mean rate of right-lateral displace-ment along the Median Tectonic Line fault system is estimated at 6-9 meters per 1, 000 years.
(3) Fault planes of the Median Tectonic Line, as far as observed at many outcrops in this area, generally dip 60°-80° N or almost vertically. Some features preserved in the shat-tered zones indicate the right-lateral faulting, accompanying with slight uplifting of the northern blocks.
(4) In this area, generally speaking, northern blocks of these active faults have been up-lifted. However, rates of vertical displacement along one strand of these active faults are locally different, and recent faulting accompanied with wavy deformation or transcurrent buckling. Vertical displacement along the whole length of the Median Tectonic Line from central Japan to Kyushu shows the scissoring on both sides, that is, the northern blocks of the fault have been uplifted in its eastern part and vice versa in its western part.
(5) As to stream offsets along the faults, it indicate that the longer are upper streams from faults, the larger are stream offsets, which amount to 1.5 or 2 kilometers in maximum (Fig. 10). It is concluded to have been dislocated at almost uniform rates at least during the latter half of the Quaternary.
(6) No great earthquake has occurred along the Median Tectonic Line in the historical time, though there are many geological evidences of quite recent fault displacement probably accompanying with great earthquakes. Tectonic creep along the fault lines is not yet found in the investigated area. It is, therefore, highly possible that a great earthquake may occur along the Median Tectonic Line in near future.

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Before the conquest of the Spaniards, the village in Mexico widely spread out, and the inhabitants had settled along the valley near the hills where was an adequate water supply.
The Spaniards brought together into the center of the village these population clusters from the outlying settlements, to control the inhabitants and to f aciliate taxation. The political and religious power was simply transfered to new ruling group represented by Spaniards. However, many of old principales were maintained by the Spanish conquerors.
In most village in Mexico with a population of about one thousand inhabitants or more, there is a regular weekly market day once or twice a week. The market place is located near the center of the village, but most of it usually is in the open and unprotected area from the weather in the shade of tall old tree (Fig. 2).
At Tepeojuma (Pue., Mexico) the market day is held on Thursday only, and held on Monday and Friday at Atlixco, and on Tuesday and Saturday at Matameros. This system makes posible a wider exchange of local goods among the inhabitants in West Puebla.
On this particular day the inhabitants very early in the morning from all the outlying areas stream into the center of the village with their handicrafts and other wares they may have for sale or exchange ; the men on sandals (huaraches), the women and children mostly barefoot, and from near towns by trucks and near villages by the donkey with their family (Fig. 3).
Usualy each of them has a his own spot in the market place where he regularly arrange their belongs on the ground. For this privillege he must pay 12 pesos 45 centavos a month to the municipal government of Tepeo juma. There, the long, amusing business of bargaining begins, and they eat, speak and hear the news and music. In this market acquaintances are made with people from other villages (localidades). In this way the plaza plays an important part in the structure of the town and village.
In addition to the economic functions, however the plaza performs important social, cultural, historic, religious and recreational functions as well. In Mexico in some case activities are directly oriented toward recreation; in this plaza some groups gather around one or more guitar players in the open music hall (quiosco). In this way the inhabitants have good time of this plaza day and fiesta day here.

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At a youthfully dissected volcano, its initial landf orm can be restored correctly. There-fore, quantitative analysis of erosional landf orm is possible. The result may forms a basis of studies of slope development at general slopes. Erosional process of Mt Yotei, a typical strato-volcano, has been studied by morphometric analysis as an example.
Connecting contour-lines smoothly over valleys, initial contour-lines can be obtained. The difference between the radius of the circle with the same area encircled by a certain initial contour-line and that of present contour-line at the same height gives average amount of slope recession at the height. Taking the altitude along ordinate and the radius along abscissa, averaged slope plofiles are obtained. Altitudinal changes of the amount of erosion are as follows at the upper slope the amount of erosion is small and nearly constant or slightly increasing with the distance from the head of the slope. At a certain point of the mid-slope, which is a kind of critical point, it increases rapidly. After reaching the maximum, it decreases rapidly and at the foot of the slope, it becomes nearly zero. Such altitudinal change of erosion is well explained by HORTON's equation on surface erosion. By HORTON's equation, the depth of erosion E at a distance 1 from the watershed is represented as follows;
E=K•lⁿ sinα/tan^n/2α-E_m
where n is index of turbulence. At the south and the east slope, calculated values obtained by putting n=7/10 (superturbulent condition) well coincide with measured values (Fig. 6). At the higher parts of the slope above the critical point, effects of erosional processes by gravi-tational actions such as soil creeps, landslides etc. have been considered.
From simplifying HORTON's equation, partial differential equation on slope development is lead,
∂y/∂t=Kx∂y/∂x+D_m
It is assumed from Fig. 3 that the starting point of intense channel downcutting (critical point), the point of maximum erosion and the terminating point of erosion migrate toward the head of the slope as erosion proceeds. The assumption is supported by the solution of the equation with the initial condition of an exponential slope similar with Mt Yotei. It is also confirmed by the results of morphometry at the Iwaki and the Rishiri volcanos.

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