The author has found such an interesting fact that the concentration of saline pore water influences the bearing power of earth foundation, i. e. the more saline the concentration of pore water becomes, the more decreases the value of compression test (qu). He has attributed the cause to dispersion owing to: base, exchange activity of Na-ions. Moreover he discusses possibility of katagenesis around clay particles in an alkaline, environment under reduction potential.
The weathering of rock loosens the combination of rock forming minerals and increases the porosity of rock, It decreases the strength of rock and forms the weakpart. The porosity changes with degree of weathering. Therefore by measuring of the porosity we can express quantitatively on the state of the weathering of rock. Accordingly the measurement of porosity is useful to judge the degree of the weathering of rock.
Japanese National Railways, famous for its Kammon undersea tunnel, is now carrying out his next marine geological survey in three localities, i. e. Tsugaru, Akashi and Naruto Straits. We can have much more useful methods than in Kammon days, and so the secret of deeper, wider, and rapidswifting sea bottom is revealed step by step by tight combination of all possible survey works.
1. The Northern Joso upland is a diluvial terrace consisting of two surfaces nominated Juri-face and Genpoji-face, the specific height of which in comparison with the alluvial plain are more or less 10 meters and 15-20 meters, respectively. 2. Paleozoic and Granitic rocks found in the eastern margin of this area compose the base rock under the terrace gravels. This forms a foundation of the Kanto Tectonic Basin, inclining to the south-east with considerable undulations. Between these terrace gravels and the base rocks intervene the sediments covering the whole base made up of a large scale of alternation, gravelly and muddy layers which is liore than 100 meters thick, and considered to be identified with the Narita group. Furthermore, the fine grained rocks thought to be formed in pliocene or miocene epoch is formed under the afore mentioned sediments covering a part of the northern margin of this area. 3. Due mainly to these geological environments, the deep ground-water is for more dominant in the west and southwest than any other directions, supplying groundwater to the law land of the eastern district of Kinu giver around Simodate City, thus forms an eminant flowing well zone there. As for the groundwater of terraces themselves, the lower Jari face is superior to the Genpoji face, concerning the shallow one, while deep ground water isn't dependent on such a terrace configuration but dominated by the geological structure of the Kanto basin. In this respect, it is thought to be able to expect a considerable amount of artesian groundwater in the gravelly layers (Yamato, Shimozuma and Kyowa formations) belonging so-called “the Narita group”, although slightly inferior to thoso around Shimodate City.