著者

上田 信三

出版者

The Association of Japanese Geographers

雑誌

地理学評論 (ISSN:00167444)

巻号頁・発行日

vol.11, no.7, pp.616-630, 1935-07-01 (Released:2008-12-24)

参考文献数

7

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The Hida Range (about 3000m height) runs from N to S at the NE extremity of the Inner Zone of South-western Japan. Near the peaks of this range, between 2800m and 2300m, are remnants of the old erosion surface that were completed during the previous cycle. They are surrounded by steep valley walls of “aufsteigende Entwicklung” (Fig. 1) that show recent rapid uplift of the mountain land (Fig. 3). The two Rivers Kurobe and Takase flow from S to N, dividing this range into two or three parallel mountain chains. The longitudinal profiles of the valley floors (Fig. 2, 7), which are steep in the uppermost part, become gradually gentler, and at 1500-1300m have already graded slope of full maturity. These erosion levels are called Upper Stream Levels (Daira. Level in the R. Kurobe and Yumata Level in the R. Takase). In their middle parts the inclination becomes again very steep and the valley form changes into young narrow gorges (Fig. I IV is a transverse section of the Daira Level, while II and III are those of the gorge). Here we find many knick points, which are called Middle Stream (or Simorôka in the R. Kurobe) Knick Points. The tributaries of these rivers also belong to the same type (Fig. 3). The author traced and reconstructed the older erosion levels in the valley floors, which were formed during a stationary period of the earth movement. From these data he concludes that there were two phases of elevation -Pre- and Post Upper Stream Levels in this district.