Two types of larger tectonic lines of different ages in Japan are compared, and several differences between them are indicated. Some considerations are made as to the relations between the tectonic lines and the corresponding crustal movements of each age. One, named Kurosegawa-type, is of late Palaeozoic and is represented by the Kurosegawa Zone, which divides the Chichibu Zone, into the Northern and the Southern (or Middle) Subzones, the non-metamorphic Carboniferous-Permian areas in the Outer Zone of Southwestern Japan. The characteristics of the tectonic lines belonging to this type are as follows. They are, generally, several kilometers wide, showing curved figures in accordance with the general trend of the folded structure and the general boundary lines of rock facies of the area. A certain type of igneous bodies, generally lenticular or elongated, small in size, is acompanied along these lines, which is generally represented by granite or granodiorite with protoclastic texture, but by more basic rocks in some cases. Na_2O is said to be richer in some of these granites than in those distributed widely in Japan. Mafic minerals are generally changed into chlorite, and no conceivable thermal effect is seen in the wall rocks. Along these lines there often occur patches or blocks of Silurian formations or crystalline schists, which are quite exotic not only to the areas but also. to Japan generally, so far as the surface exposures are concerned. In the Kurosegawa Zone, these exotic masses generally occur along the margin of the granite mass in shape of half-enclosed "xenoliths", and are supposed to be brought to the present sight from the deeper part, at the time of the granite intrusion. The Silurian rocks, mainly composed of acid volcanics, are quite unaffected by any type of regional metamorphism, and are supposed to have been a basal part of the Palaeozoic rocks of the area. The crystalline shists, represented by such leading types as epidote-amphibolite and garnet bearing biotite-schist, were, probably a part of the basement complex, which had been metamorphosed before the deposition of the Silurian. Along these lines, Permian rocks are frequently metamorphosed into crystalline schists of low metamorphic grade, where phyllites and chloriteschist are the leading types. These characteristics show that the tectonic lines of this type appeared in late Palaeozoic, in the course of, or as an extension of folding movement in the geosynclinal deposits, which were still plastic enough to be folded strongly. The other is named Kesen-numa type after the Hizume-Kesennuma Tectonic Line, which runs from NNW to SSE, at the central part of the Kitakami Mountainland, Northeastern Japan. It appeared first in the early Cretaceous. Two tectonic lines also with NNW-SSE direction, on both sides of the Abukuma Mountainland to the south of the Kitakami Mountainland, belong to this type. The characteristics of the tectonic lines of this type are as follows. They are rectilineal, cutting the general trend of the folded structure of the area, and are supposed to have fault planes of high angle. Such strange blocks as those found along the tectonic lines of the former type are not found. Among the various kinds of intrusive bodies found along the tectonic lines, granites are the largest. Some of them are mylonitized, but none of them is proved to be protoclastic. Some of the granite masses are characterized by their uneven grain size and zoned plagioclase. These features suggest that they. crystallized in the shallower part of the crust. Thermal metamorphism is `remarkable, in this case, and the metamorphic aureole comprising sillimanite-, andalusite- and biotite-hornfels has 2-3 kilometers' width. Along the tectonic lines, the country rocks and a part of the intrusive bodies are sheared and mylonitized, but no crystalline schist is found related to the faulting. The present type

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