五島列島と西彼杵半島間の第三系基盤岩類,特に長崎県下の花崗質岩類と関連して

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Since the first discovery of the thermally metamorphosed rocks characterized by the growth of large andulsite porphyrobrasts in 1959 from Ainoshima, the author has studied the Ainoshima and Enoshima formations in relation to the granitic rocks of a Cretaceous age. The lithologic features of the Ainoshima thermally metamorphosed rocks were already delivered in the previous Ainoshima papar. The Enoshima formation which is mainly composed of slates, tuffaceous sandstones, tuffs, conglomeates, volcanic breccias and lavas is intruded by the Hirukojima granodiorite which bears a closed relation to the Nishisonogi granitic rocks, and is disconformably overlain by the early Paleogene Minamise formation in which the andesite and porphyrite pebbles consisting the Enoshima formation are abundantly found. The writer included the Enoshima in the Kammon group and compared it the Ainoshima formation from the lithologic features. It should especially noted that these two formations contain the thin, somewhat impure limestone layers and large limestone pebbles. In this paper, furthermore, the geologic structure of this area was discussed based upon these Tertiay basement rocks arranged from east to west. The author thinks that these basement rocks are exposed along the Otatejima anticlinal axis passing from Terajima to Otatejima.