The faults accompanied by intermediate and deep earthquakes under Hokkaido and its neigh-bours are discussed, based on the data of P-wave radiation pattern by SASATANI (1976). Though two nodal planes are drawn from the analysis, the present author shows that the steeper nodal plane which would correspond to the fault plane at the hypocenter runs parallel to the boundary of each tectonic province. This fact shows that each tectonic unit such as Okhotsk sea basin, Hidaka orogenic belt and Japan sea basin spreads its root deeply into the intermediate-deep earthquake zone, and its formation is intimately related to the zone, though it dips straightly away from the trench.

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Typical fecky gneisses with a very peculiar structure, with a lot of porphyroblasts consisting of Al2SiO5 polymorphs formed in relation to the diaphthoresis described in the previous paper (WATANABE et al., 1978), were found by the present authors in the Oinudaira and Shinden areas, Tabito Town, Iwaki City, located along the "Koshidai-Takaboyama-Daioh・in" structural belt. Flecks are small scale metamorphic differentiation structures characterized by dark core (melanosome) consisting of alumosilicate polymorphs plus magnesiosilicates, surrounded by granitic mantle (leucosome or leucorim). Melanosome is composed mainly of kyanite, sillimanite, mullite, andalusite, corundum, cordierite, anthophyllite and green biotite. Leucosome, on the contrary, consists of quartz, oligoclase, potash feldspar, muscovite and biotite. Such mineral segregations formed by metamorphic differentiation are important source of information on diffusion processes in metamorphism, namely K, Na and Si migrate from core to manite, whereas AI, Mg and Fe from mantle to core. Theories concerning the fleck development mainly fall into two categories: (1) metamorphic differentiation of a previous homogeneous material within internal system, and (2) porphyroblastic growth under ionic migration with hydrous vapour from external system and succeeding alteration of alumo-silicate polymorphs and cordierite. "Flecky gneiss problem" is very important for studying a metasomatic migration of such ions (basification into front zone of anatexis area and leaching product of granitic component, vice versa) and ionic activities through granitization process, as cited by SVENONIUS (1907, 1917), GEIJER (1923), MAGNUSSON (1925), BACKLUND (1936), HJELMQVIST (1942), DURIETZ (1949), BERGSTROM (1959), LOBERG (1963), MEHNERT (1968), RUSSELL (1969), FISCHER (19 70), KRESTEN (1971) and DAHL (1972). As far as the geological evidence in environs shed light on, it may be concluded that the flecky gneiss--a kind of retrograde metamorphics (diaphthorite, strictly speaking) originated from high-grade gneisses belonging to the former episode, which is the Takanuki metamorphics--was metasomatically formed together with fleck development connected with migmatization of the subsequent stage of the Abean orogenic movement (MINATo et al., in press), and that the rock was upheaved as the allochthonous uplifting bodies with "Schuppen" structure, along the belt. This is a preliminary article on flecky gneiss and brief introduction to the significance. The detailed description of the rock will be given in a forthcoming paper.

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The purpose of this study is firstly to investigate the growth stage of shell at which the replenishment of earlier chambers and the crust formation occur in connection with some benthic foraminiferal species and secondaly to clarify its taphonomical significance. When the replenishment and the forming of crust occur, shell weight is increased, rapidly. In consequence of this the settling velocity of shells in still water is accelerated Foraminiferal shells are placed in still water with sediment particles using the emery-typed tube and settled material are cut into nine samples according to the order of their settlement, and the size of shells is compared with that of quartz spheres settled during the same time periods. In most of the species studied, the relative rate of increase in weight per surface area of shells is larger than that of quartz spheres in the stage of smaller shell size, but in the stage of larger shell size it shows the inverse relationship. In other words, a change of the relative rate of shell mentioned above takes place abruptly at certain growth stage. It does in the sample in which the largest numbers of individual occurs or in the sample in which the individual numbers decrease abruptly in the coaser grained samples as opposed to that sample. On the other hand, the shell form change of each foraminiferal species is not observed so distinctly through all the growth stages. These facts indicate that the shell weight of most species of investigated foraminifers becomes heavy abruptly by the replenishment of earlier chambers and/or the forming of crust after coming into the various type of full-growth stage of each species. The phenomenon of this sort is widely known regarding marine benthos with calcareous shell such as bivalves. This suggests a need of particular consideration in using size-frequency data in the taphonomical analysis of benthic foraminifers.

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The geologic sequence in the Osako district, Nara Prefecture, is subdivided into following four formations, namely the A, O, B and C formations. The A and C formations are equivalent to the A and C formations, respectively, in the Mt. Daifugen district which was described in Part I (Yamato Omine Reserch group, 1976) of the present work. The A formation is composed of sandstone, mudstone and their alternation. The O formation consists mainly of mudstone, intercalated with some layers of sandstone. The muddy matrix encloses variously shaped rocks (sandstone, chert, limestone and greenstones) of a few millimeters to tens meters size. The enclosed rocks yields sometimes fossils such as fusulinids, conodonts or hexacorals. The B formation consists of mudstone, limestone, greenstone, chert and sandstone. The limestone body is large and thick, and is exposed widely at high cliffs in several places. The C formation is made up of chert, intercalated with layers of mudstone, sandstone, limestone and green stones. Some limestones and cherts of the B and C formations yield Late Triassic conodonts. Some rocks enclosed in the O formation are exotic blocks simultaneously deposited with mud because the blocks are in sedimentary contact with the muddy matrix. On the basis of the chaotic facies and the various fossils, it is considered that the part of the O formation enclosing various blocks is compared with olistostrom.es reported from the deposits in the Northern Apennines (ABBATE et al., 1970). In the Osako district, each formation forms homoclinal structure inclined northwardly. The O formation is disturbed all over by low angle thrust faults. The geologic relationships among the A, O and B formations are considered to be fault contacts with gentle dips nearly parallel to their bedding planes. These faults correspond collectively to the Butsuzo tectonic line. However, the A formation must have been originally overlain by the O formation with a sedimentary contact.

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