Lacustrine deposits and terrestrial volcanic products of Pliocene to Middle Pleistocene age are widely distributed in the eastern part of Toya Lake. Based on some unconformities, Pliocene and Pleistocene deposits are divided into the following major divisions: the Kitayuzawa Formation, the Rerukomabetsu Formation, the Andesite Member, the Sohbetsu pumice flow deposit and the Takinoue welded tuff, the Kimobetsu welded tuff, and the Tokushunbetsu clay member. Lower to Middle Pliocene deposits of the Kitayuzawa Formation were accumulated in two polygonal collapse sub-basins, which form the so-called Kitayuzawa basin. This basin was changed to a tectonic basin in Middle Pliocene. Upper Pliocene and Pleistocene deposits, which are represented by the Rerukomabetsu Formation, the Andesite Member and the Tokushunbetsu clay member, were piled into the valley and the dammed lake of the Osarugawa tectonic basin. Three magnetic polarity zones, namely: the lower-predominantly reversed, the middle-normal and the upper-reversed, could be recognized on the basis of paleomagnetic analysis of the Kitayuzawa and Rerukomabetsu Formations. From bottom to the top, these polarity zones are believed to correspond to the late Gilbert reversed, the Gauss normal and the early Matuyama reversed polarity chrons, respectively. Fossil pollen assemblage of the upper part of the Kitayuzawa Formation is characterized by high concentration of Picea which indicates a cooler climate than at the present. The Rerukomabetsu Formation is divided into 9 pollen zones: RK-I〜IX in ascending order. RK-I and RK-II Zones are dominated by Taxodiaceae indicating a warmer and moister climatic condition. In RK-III Zone, Picea increases but Taxodiaceae decreases. RK-IV Zone is characterized by high concentration of Picea, the presence of Selaginella selaginoides and a variety of herbs, and thus indicates a cold dry climate. Zones RK-V, RK-VII and RK-IX show high concentration of Picea, whereas Zones RK-VI and RK-VIII show high concentration of Taxodiaceae. It indicates that climatic changes occurred repeatedly. The two pollen zones, namely: TS-I and TS-II, inside the Tokushunbetsu clay member represent climatic change from mild to cooler than the present. Based on the radiometric ages, magnetostratigraphy and pollen assemblages, RK-I and II Zones of the Rerukomabetsu Formation may be correlated to the upper part of the Horokura Sandstone-Mudstone Member of the Lower Pliocene Fukagawa Group in Central Hokkaido. The climatic change from warm-wet in Zone RK-II to the cool and cooler-dry in Zones RK-III and RK-IV may be correlated with that recognized at the boundary (which also represents the Gauss/Matuyama boundary) between the lower and upper parts of the lower part of the Ikeda Formation which belongs to the Tokachi Group in Eastern Hokkaido. The climate recorded in the Tokushunbetsu clay member is correlated to cool stage of Middle Pleistocene, detected in the upper part of the Otoebetsugawa Formation distributed in the Ishikari Lowland.

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The Setana Formation is widely distributed in southwestern Hokkaido and yields numerous and diversified molluscan fossils that seem to be of early Pleistocene in age. This molluscan fauna is mainly characterized by cold water elements and belongs to the so-called Omma-Manganji fauna in the Japan Sea side of northern Honshu. In the Kuromatsunai district, the Setana Formation is unconformably underlain by the Kuromatsunai Formation and overlain by the Chiraigawa Formation. From the lithologic features, this formation is subdivided into two members in the eastern part and three members in the western part of the studied district. The molluscan fauna is subdivided into three assemblages-I, II and III, which are characterized by the stratigraphic position as well as the specific composition respectively. The assemblage I, which is obtained from the lower part of this formation, consists of 20 species including the elements of the Setana fauna proper such as Yabepecten tokunagai and Chlamys islandicus, and includes about 25.0% extinct species. The assemblage II, which is obtained from the middle part of this formation, comprises 53 species and is characterized by some extinct species such as Chlamys cosibensis and C. daishakaensis. The assemblage III, which is obtained from the upper part of this formation, is characterized by large individual numbers of Mizuhopecten tokyoensis (s. s.). The assemblage III consists of 108 species which is chiefly composed of Oyashio living species such as Mizuhopecten yessoensis, Swiftopecten swiftii and Turritella fortilirata. About 5.6% extinct species are included in this assemblage. From the representative species and the ratio of extinct species, the assemblages I and II are rather in close association with each other and are corresponded to the Setana fauna proper. On the other hand, the assemblage III appears to be much younger in age than the Setana fauna proper (assemblages I and II). Namely, the abovementioned faunal change is most likely attributed to the change of environmental conditions with the lapse of the geologic time.

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Orthoquartzite fragments were firstly found from Miocene formation overlying Joetsu metamorphic rocks in Minakami district. The conglomerate which yields these orthoquartzite fragments is mostly composed of sandstone fragments, but those of shale hornfels, chert, felsic rocks, altered dacitic rocks, altered basalt and crystalline schist are included. In spite of the durable lithology, the orthoquartzite fragments posses a high roundness (0.34〜0.73) in comparison with the other fragments. This indicates that they are reworked fragments from pre-Neogene formations. The Tokurazawa Formation distributed in the Joetsu district is one of probable source of these orthoquartzite fragments, because many orthoquartzite fragments have been found from the Lower Cretaceous Tetori Group with which the Tokurazawa Formation is a correlative.

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Guangzhou-Conghua Fault-Tectonic Belt is extraordinarily significant not only in its long continued activity from the early Paleozoic up to the present but also in its important role playing the number of tectonic events in the Southeast China. The effects of the repeated faulting of this belt are approved by controlling the formation of the Caledonian metamorphic rocks, that of the early Paleozoic migmatite, the distribution of the late Paleozoic strata, intrusions and eruptions of the Jurasso-Cretaceous igneous rocks and the formation of red basin as well as the formation of the Quaternary sediments, distribution of hot springs, earthquakes and the topography. These various kinds of tectonic events and phenomena related to the faulting are in accordance with three stages of tectonic movements in China, that is, Indosinian, Yanshanian and Himalayan except for those at Neotectonic stage. The dynamic aspects of the faulting is explained by alternation of compresso-shear and tensional shear, which reveal the crustal condition and its development since the early Paleozoic.

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The diaphthoresis concept" speculated by Sugi (1933, 1938) in the Abukuma terrain, Japan, has attracted the interests of many geologists for a long time. However, it is rather difficult to note that most of their works on it could really materialize his concept. In 1978, the present authors found and described the diaphthorite (Takaboyama diaphthorite mass) in the Koshidai-Takaboyama-Daioh-in Structural Belt (Abbrev. K-T-D SB). Ever since, the diaphthorite problem in question has been shed light on in detail. The "Koshidai diaphthorite mass" in question, located in 25 km north of the abovementioned "Takaboyama diaphthorite mass" is distributed along the K-T-D SB as well and occupies an extent of about 10km in length and 0.5 to 1km in width. The mass is petrogenetically divided into six rock facies, viz. (1) porphyrolastic quartzose gneiss, (2) andalusite porphyroblast-bearing porphyroclastic biotite gneiss, (3) gabbro-amphibolite, (4) blastomylonitic biotite gneiss to schist, (5) chlorite schist and (6) tremolite-cummingtonite-anthophyllite schist. The pre-existing metamorphics, prior to the diaphthoresis superimposed to the mass, are originally estimated to be high-grade quartzose gneiss and biotite gneiss of the "Takanuki Series". As tabulated in Table 2, the questioned diaphthoresis is characterized by metamorphic degradation (Kata-, Meso- to Epi-zone), rock facies deterioration (S1〜S6), textural degradation (granoblastic to extremely lepidoblastic texture) and petrochemical change (basification): decrement for SiO2, increment-decrement for Al2O3, Na2O and K2O, increment for Fe2O3, FeO, MgO and CaO. It is conclusively emphasized that the above-mentioned "metamorphic-metasomatic Convergence" owing to diaphthoresis had happened before thrusting up along the "Koshidai Thrust Zone" to Obergebirge ("Ishizumi and Saibachi zones" of the "Gozaisyo Series") as an allochthonous septa.

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A convenient program for drawing atomic arrangement in crystals has been written in BASIC. By the program, a, b or c-axis projection figure can be obtained for any space groups of crystals. Unit cell dimensions, atomic coordinates an an asymmetric unit, ionic radius of each atom and symmetry operation matrices are required for the drawing. Three modes of drawing projected along any crystal axis are possible such as 1) atom projection without erasing underlying circle-lines of atoms, 2) circular drawing of atoms by erasing underlying lines, and 3) spherical drawing of atoms. Quartz structure was shown for an example to explain how to use the program.

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