Many landslides were caused by the heavy rain of 17 August, 1968 in northern part of Mino-kamo city and the surroundings, Gifu Prefecture. The writer considered the relation between the distribution of landslides and geology, with the aid of aerial photographs taken after the heavy rain.
The area is composed mainly of alternation of Paleozoic sandstone and chert. Number of land-slides per unit area is 20-30 in average, and the maximum 60/km². In most cases, crown of landslides occur near the ridge of mountains, where strongly weathered sandstone crops out.
It was observed that crowns of landslides arrange along the boundary between sandstone and chert. The height of the boundary is the same of ridges of weathered sandstone. This line, also, corresponds to the height of the Seto terrace (sedimentary plane of Plio-Pleistocene Seto group.)

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