The lumbar vertebrae, sacrum and coccygeal vertebrae of Desmostylus mirabilis NAGAO from Keton are described with a discussion on its vertebral formula. The characteristics of the lumbar vertebrae are nearly the same as in the thoracics (INUZUKA, 1980) but the following differences are observed: Body is wider; costal processes short, depressed dorso-ventrally, protruded horizontally and at right angle ; spinous process longer foreand-aft, inclined forward slightly, not broadened transversely at the tip; accessory processes absent. Sacrum is composed of five segments, the first two of which form auricular surface; outline of sacrum triangular; a broad interarcuate space present between the first and the second segments; sacral ridge not so developed; spirous process not high. Coccygeal vertebrae is short; vertebral arch and transverse processes not developed; hemal arch probably absent. The vertebral formula of Desmostylus, 7-13-4-5-11, as confirmed by the present study, is very peculiar, being different from any of Sirenia, Proboscidea, Monotremata and Perissodactyla.

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Earth current can be observed as potential difference between two points. Commonly, earth current changes with geomagnetic field, magnetic storm and so on, while this current will show unusual change when shock occurs. The observation of earth current has become one of the most effective measures for the earthquake prediction in China. From this point of view, we have been observing earth current at the Atotsugawa Fault, one of the first class active faults in Japan, since 1976, to make clear the relation between earthquake and earth current. A local shock (M:3.6) broke out at 4:55 a.m. on September 16, 1978. The epicenter was located on the Ushikubi fault, parallel to the Atotsugawa Fault, 7 km northwest from Amo observatory point. About an hour before this shock occurred, a disturbance of the earth current started to be observed at the parallel component set along the fault. Almost at the same time as the shock occurred a disturbance began at the cross component. These disturbances of both components were the same pattern. The degrees of variations were 4mV (parallel component) and 2.5mV (cross component). In order to make clear the disturbance when the shock broke out, discussed the influence on earth current by examining the data of magnetic field, magnetic storm, rainfall and thunder. We used the data between 1978 and 1980. Judging from this result, these disturbances were considered to be related with the occurrence of shock on September 16, 1978. If these disturbances occurred as the result of the shock, we might explain this mechanism as follows: the disturbance of earth current which changes quickly first and then recovers slowly was caused by flowing of water in the process of dilatancy. This fact clearly shows the nature of diffusion of water.

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The bearing of orthoquartzitic clasts in the development of the Japanese Islands was first discussed by TOKUOKA (1967) and their precise description was given in 1970 by the same author. Orthoquartzitic clasts from the Muro group have similar characteritics with typical cratonic sandstones such as Sinian quartzites in China or other Precambrian sedimentary quartzites, and it is generally accepted that these were derived from the Precambrian cratonic basement underlying the Japanese Islands. However, the examination on orthoquartzite itself has not been fully done, especially of their occurrence and textural properties. These problems are reexamined here in detail. Eighty-nine orthoquartzitic clasts which were randomly collected by the KISHU SHIMANTO RESEARCH GROUP (1970) were observed precisely under the microscope. It is very interesting that there are many kinds of color in orthoquartzitic clasts, which are shown as colored photographs in Plate I, and that these are quite unexceptionally constituted from rounded or well-rounded quartz grains, and furthermore, that there are found several pitted grains. These facts indicate apparently that orthoquartzitic rocks were originally formed under dune environments. Textural properties of orthoquartzitic rocks were reexamined in detail after Friedman's method (FRIEDMAN, 1957 and 1962b). Grain-size distribution was obtained in twenty-five specimens of the KISHU SHIMANTO RESEARCH GROUP (1970) and in thirty-nine ones of TOKUOKA (1970). On the basis of grain-size parameters, orthoquartzites, which occur as clasts in conglomerates of the Paleogene Muro group, are safely assigned to have been formed originally under beach and/or dune environments.

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Abundant orthoquartzitic gravels were found in the basal part of the Osaka Group in the Senriyama Hills, Osaka Prefecture. The gravels which contain orthoquartzite are mostly composed of chert, accompanied with numerous acidic pyroclastic rocks and acidic igneous rocks. On the other hand, the gravels without orthoquartzite are poor in acidic pyroclastic rock. Abundance and limited distribution of orthoquartzitic gravels accompanied with many acidic pyroclastic rocks suggest that the source area of them may be restricted within narrow limits.

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