The lithological aspects of the Izumi group, the notes of general geology and the structural geology are described. The elongated area of Northern Shikoku is covered by the marine elastic sediments, the upper Cretaceous Izumi Group, which is distributed along the Median Tectonic Line of the Southwest Japan. They consist of a large volume of elastics. The stratigraphic succession of the Izumi Group in the investigated area is summarized as follows in ascending order. / Lower subgroup / Formation A : conglomerates and sandstones / Formation B: sandstones with thin shales / Formation C : alternation of shales and sandstones / Middle subgroup / Formation D: alternation of sandstones and shales lower part predominated sandstones / Formation E : shales alternated with sandstones / Upper subgroup / Formation F: chiefly-coarse grained sandstones, partly with sporadic gravels / Formation G: alternation of sandstones and shales / Formation H: conglomeratic sandstones One subgroup shows one sedimentary cycle, the lower part of which is dominated by coarse-grained elastic rocks. Various types of graded bedding are shown in Figs. 3 to 6 and Tables 1 to 7. The direction of the sedimentary transport is determined as being from northeast to southwest by the analysis of primary sedimentary structures. As a result of the comparison of the sedimentary environments, the main part of them are considered to be a kind of submarine fan
