Ore deposits at the Kishu Mine are fault-filling veins in Miocene sandstones and shales which surround the so-called "Kumano acidic rocks". Chalcopyrite and pyrite are the ore minerals. The vein systems strike roughly in three major directions, namely E-W, N45W and N-S. The first two directions have chalcopyrite-pyrite veins while the last has only pyrite veins; fault displacements in the last are far greater than those in the first two.
For several years it has been thought that bonanzas are mostly confined to the sedimentary rock. The existence of bonanzas is very probable in certain sandstones (called the C members at this mine). Also, it was thought that shales, called the B members, play the role of cap-rocks. However, our latest studies have indicated that although control of the ore deposits by certain layers is certainly true, it is not the sole factor. We have been able to find eight centers of mineralization in this mining district by drawing "copper grade contours". The amount of displacement of the E-W and N45W veins is largest at the centers and decreases gradually outward enabling us to draw "equidisplacement contours".
Through detailed investigations, it was found that there are several flat dornes or basins in a layer which seems monoclinial against the Kumano acidic rocks. Basins and plunging syclines are of small scale. Structure contour lines drawn to show the dome structure coincide with the "copper grade contours" and the "equidisplacement curves". It is concluded that shoots at the Kishu Mine are controlled by the dome-like structures, a fact which will be an important indicator for prospecting.

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Among geologic units in the Yanahara area, clayslate, volcanic rocks, diabase and epi-quartz diorite of Triassic age are of outstanding importance. Diorite, breccia-liparite and dyke rocks, and locally Tertiary and Recent sediments are also present.
The old volcanic rocks which include lavas and tuffs are intercalated in the lower part of the clayslate, and are the most fruitful mother rocks for high grade pyritic deposits of the Yanahara Mine. We call. this unit of volcanic rocks the "complex zone", because of its high complexity in petrological as well as structural features.
The ore shoots are restricted to the "complex zone", where veins containing them swell. The particular shapes of ore deposits are probably related to some tectonic movements in the area.
As a guide to new ore deposits, the above concepts should be very useful during future prospecting.

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Fresh and altered specimens of diabase and phyllite from the Sangasho Mine, Miyazaki Prefecture, have been analyzed for minor elements, such as Cu, Cr, Ni, Mn, Ti, V and Zn by means of chemical and spectrographic methods.
The content of these minor elements varies with the grade of mineralization. The country rocks and ore minerals usually contain Ni, Cr, Ti and V; these_are more concentrated in ores closely associated with diabasic rocks. It therefore is presumed that the Sangasho deposits have a genetic relation to these basic rocks.
The effects on the country rocks during the formation of "Kieslager" were restricted to within a few meters from the ore bodies. (These effects are especially shown by the content of Cu and Zn.)
It was also found that the Sangasho diabase generally contains less Cu and more Cr than any basic rock hitherto reported.

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Jarosites are associated with limonite deposits in the environs of Mt. Kurikoma.
The limonite and jarosite ores grade laterally into each other within a single bed, i.e., from jarosite with thin layers of limonite, through alternating layers of limonite and jarosite, to limonite with thin layers of jarosite.
At places the jarosite contains diatom earth composed of several species.
Chemically, the ore is characterized by a higher content of Na₂O than the average (i. e., less than. 1.0% Na₂O) of other jarosites in Japan.
Jarosite-bearing limonite ore at the Omori Mine, occurs under a limonite bed which is characterized. by plant impressions. This ore is composed of goethite and fine particles of jarosite cemented by goethite. Fragments of plagioclase, quartz and rocks are enclosed in the ore.
The result of the spectroscopic analysis confirms the existence of Fe, Al, Na, and K in the ore. The X-ray powder diagram and differential thermal analysis curves show that this ore is a mixture of goethite and jarosite.

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