The Myoko Volcano Group, consisting of Yakeyama, Myoko, Kurohime, lizuna, Madarao and Sadoyama Volcanoes, is situated in the boundary area between Nagano and Niigata Prefectures, Central Japan. Most of the volcanoes are distributed along the anticlinal or synclinal axes of basal Neogene strata. Except for Sado-yama and Madarao Volcanoes, the volcanic cones are arranged in a north-south trend with each nearly equal interval (about 8 km), and generally the age of each volcano tends to become younger northward. The rocks of this Volcano Group, characterized by hornblende andesite, are in striking contrast to those of sothern part of Fuji Volcanic Zone. They also differ from the basement volcanic rocks with biotite phenocrysts. Both Myoko and Kurohime Volcanoes are double stratovolcanoes of the latest stage of the Quaternary. Their activities may be divided into four stages; the older stratovolcano, the younger stratovocano, the caldera and the central cone stages. Myoko Volcano is constructed by a large amount of lava flow, pyroclastic flow, pyroclastic fall and mud flow. The rocks are characterized by common occurrence of hornblende and/or olivine phenocrysts, and by larger petrographical variation. On the other hand, in Kurohime Volcano, lava flows are predominant overwhelmingly, and pyroclastics are subordinate. Most of the rocks are augitehypersthene andesites, and the petrographical nature is rather uniform.

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The structural complex of so-called Pipairo gneissose granite which is situated at the northern part of the Hidaka metamorphic belt, is subdivided into three structural units such as the falling-star structure at the center, three phacolith-like masses and arch structure of a phacolith with inclination to west at the eastern part (Figs. 1, 2 and 3). They are not all the gneissose granite but are composed of schistose biotite hornfels, banded gneiss, biotite or cordierite migmatite and granitic migmatite some of which might be of melted to be the gneissose granite. The structural analysis from the mesoscopic as well as microscopic points of view revealed some results as follows: the falling-star body moved upward to south probably at the syn-kinematic stage, while other phacolith-like bodies were emplaced and thrusted up toward east probably at the late-kinematic stage.

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Various geological and paleomagnetic evidences strongly support the concept of continental drift since the Middle Mesozoic. It might be taken, as already stressed by a number of authors, as a geological "fact". The theory of ocean-floor spreading and plate tectonics to date seem, however, insufficient to interprete the cause and real mechanism of continental drift. In my opinion the decisive cause of continental drift was the slight expansion of certain horizon within the upper mantle due to heat accumulation during relatively quiet periods since the Latest Precambrian through the Late Paleozoic. The essential mechanism of continental drift seems to have been the " active" advance of continental lithospheres, through the overriding of neighbouring oceanic (Pacific) floors beneath them, corresponding to the new generation and spreading of the Atlantic and Indian ocean floors. As well-known, several localities at the tails of drifting continents are characterized by the Early〜Middle Mesozoic basic (tholeiitic) volcanic eruptions, the frontal regions of drifting continents adjacent to the Pacific being, on the other hand, marked by calcalkaline, predominantly intermediate〜acid volcanism and plutonism since the Late Mesozoic. Some genetial problems concerning these contrasted magmatisms are presented in term of the above-mentioned cause and mechanism of continental drift.

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This paper represents a review of the amino acid distribution and of the diagenetic fates of proteins in recent and ancient sediments. The diagenetic process of the organic compounds in sediments differs from that in fossils in the following two aspects; (1) the protein in sediments is suffered by active bacterial destruction especially under oxidizing conditions and (2) the resulting hydrolysates (amino acids) are polymerized with the other organic compounds therein such as carbohydrate, lignin or fat, producing humic acid or kerogen in sediments. Most of the survival amino acids in the ancient sediments are derived from the kerogen or humic acid, which may give the similar composition to the original protein at its deposition. It is suggested that the depositional environment can be inferred from the amino acid composition in the ancient sediments.

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