In the Ishigamori district, the Ishigamori, the Fukiya and the Wakamatu gypsum deposits and the Takawarabi outcrop occur in the same horizon in the marine basins.
These basins are arranged along two structure-lines, N30°E and N55°W.
The sericitization was caused by the solution which deposited the gypsum ores, but the montmorillonitization was not. The silicification and the pyrite impregnation were caused by the solution in a later stage.
The Ishigamori deposits consist.of four irregular massive ore bodies. But judging from the mode of occurrence, the original deposits are thought to consist of two bodies lower and upper, which are separated into four ore bodies by several thrust-faults.
The deposits show many structures suggesting replacement, but the cap rock is nonexistent, and judging from the general internal structure, the deposits may have been formed at the same stage with the rocks of the same horizon.
The solution which deposited the gypsum ores changed its force with time, and welled forth intermittently.
As a result of these activities, the gypsum bodies have come to show the complicated structure. However, the gypsum is not a derivative of anhydrite due to hydration; the mineral is of primary origin and was formed at low temperatues.

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Existence of the "Minenobu barrier" which separated the Sorachi basin from the Yubari basin during the deposition of the lower half of the Ishikari group, has been pointed out by many geologists.
Another fact that the formation of the embryonic structure of the Sorachi anticline had been going on during the period when the Minenobu barrier existed has also been confirmed. The author assumed that the Minenobu barrier was connected with the embryonic structure of the Sorachi anticline; in othe words, the southern part of the embryonic structure had emerged above the water. The combination of the Minenobu barrier and the Sorachi anticline is named by the writer "Akabira-Ikushumbetsu upwarping zone."
During the Neogene Tertiary, the Sorachi anticline formed due to compression from the east. At this stage, an extremely strong force was exerted on the southern end of the anticline. Therefore, the southern end was bent toward the west, and folds and faults took place on the concave side, i.e., on the west side of the anticlindl axis. Based on the above-mentioned assumption, some tectonic features of this area may be explained, especially the formation and structure of the Pombetsu-fault and the fact that the general trend of the strata in this area does not agree with the general N-S direction of this coalfield.
There is a remarkable difference in the state of sedimentation of the Ishikari group between the two areas, north and south, of the Akabira-Ikushumbetsu upwarping zone.
The stratigraphic sequence of the Ishikari group and Poronai group is remarkably different between, the north side area and the south side area. The author indicated a possiblility that the Ikushumbetsu formation in the southern area is correlated with the upper three formation of the Ishikari group, that is the Ikushumbetsu formation, the Hiragishi formation, and the Ashibetsu formation in the northern area.

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The writer studied the sedimentary environment of the Ishikari group in the Ashibetsu district, Sorachi Coal Field on the basis of the geological data obtained through surface and underground survey.
The crustal movements which continued since the latest Cretaceous period formed the Ishikari geosyncline, containing some geanticlinal upheavals, such as Bibai-Ashibetsu tectonic line named by Dr. S. TASHIRO and the Panke-Panke-Poronai upheaval zone suggested by the writer. During the deposition of the Palaeogene sediments in this geosyncline, there were intermittent subsiding movements, accompanied by the tilting of the ground.
The above-mentioned upheaval zones not only had a great influence on the deposition of the Palaeogene sediments, but also played an important role in the structural history of the Sorachi Coal Field.
The important points of the depositional process of the Ishikari group in the Ashibetsu River district are as follows :
1. The thickness of the members of the Ishikari group has a general tendency to decrease towards the Bibai-Ashibetsu tectonic line.
2. The sedimentary strata, ranging from the Noborikawa formation to the Yubari formation, have a tendency to decrease their thickness northward and southward from the Bibai-Tanzangawa line which is the sedimentational center.
3. From the last sedimentation period of the Yubari formation (accumulation period of No.8 coal seam) to the sedimentation period of the lower Wakkanabe formation, the sinking movement with northward tilting was inactive in the area between Sakipenbetsu and Right 6, a branch of the Hachigatsuzawa in the span of approximately 5.8 km, but the sinking started again with the sedimentation of the upper Wakkanabe formation which, as a consequence, directly overlies the Yubari formation.
4. During the period from the Wakkanabe formation to the Tanzangawa formation (Woodwardia formation), the sinking movement accompanyed by northward tilting became active, and the center of the subsidence in the Ashibetsu River district shifted from the Tanzangawa area to the Otanizawa area.
5. During the deposition period of the Bibai formation in the Ashibetsu River district, differential subsidence is observed. This is marked during the deposition of the Torakawa Bed, i.e., the upper portion of the Bibai formation, resulting in the locally variable thickness of the strata.
6. During the deposition period from the lower Raijo formation (Upper Corbicula formation) to the Ashibetsu formation, the center of development of the strata in the Ashibetsu River district from the Otanizawa area to the Tanzan-Jyugosenzawa area. Especially, during the deposition of the upper Raijo formation, the Jyugosenzawa area had the thickest strata.
7. There were occasional volcanic activities during the subsiding movements in the Sorachi basin, and it may be surmised from the following data that the volcanic activities had some relationship to the uplifting and subsiding crustal movements.

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The Kanagato copper mine is situated at about 20 km. N. of Ogori Station, Sanyo Railway. Ore deposits of the mine are of hypothermal fissure-filling type.
Ore minerals are mainly chalcopyrite, arsenopyrite, pyrrhotite and pyrite, accompanied by small amounts of scheelite, bismuthinite and native bismuth. Ore deposits are characterized by the presence of tourmaline as well as by a minor content of cobalt in arsenopyrite. Fissures filled with ores are shear fractures, linked with each other and running in the directions of N 20 W and N 10-20 E. Elongation of the fissure zones attains to more than 1, 000 meters. There are several zones containing ores. Ore bodies, numbering one hunderd or more in developed areas, are variable in shape such as lenses bunches, etc., and are irregulanly scattered in the fissure zones.
Ore shoots are elongated vertically, being 2-20 meters in horizontal length and 10-200 cm. in width. The west-Hobenzan granodiorite, intruding the upper Palaeozoic formation of slate, sandstone and schalstein, is the ore bringer, whereas the Palaeozoic formation are the wall rock of ore deposits. Stock of the granodiorite has slightly metamorphised rhyolite which is believed of be a member of upper Cretaceous volcanics.

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