[in Japanese]

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The Plio-Pleistocene strata in Japan is typified by the marine Kazusa group in Kanto district and the aqueous Osaka group in Kinki district. On these groups, numerous studies of stratigraphy, paleontology, paleomaganetism, and so on, were reported, and the Plio-Pleistocene boundary was discussed from several view points. The pollen flora of the Kazusa group along the Yoro river was investigated by the writer and the results are summerized as follows. 1) There are two steps in the disappearance of the Pinus trifolia flora; a) Keteleeria and Pseudolarix? become extinct at the middle part of the Umegase formation (between U6 and U10), and b) Metasequoia and Picea A, at the middle of the Kokumoto formation. 2) By the sequence of the disappearance of the Pinus trifolis flora and the pollen composition, the Kazusa group is divided into six zones. 3) The correlation of the pollen zone of the Kazusa group and the Plio-Pleistocene flora in Kinki district may be shown as follows; Zone 1...Pinus trifolia flora and Transitional flora 1 Lower half of Zone 2...Transitional flora 2 Upper half of zone 2 and Zone 3...Metasequoia flora Zone 4 ...Paliurus nipponicus flora and 4) The Plio-Pleistocene boundary, as defined in the Osaka group, should be drown between U6 and U10.

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Thermal conductivity, elastic wave velocities, and density of andesites are measured at the room temperature and pressure condition. Samples are colected from the Miocene andesitic rocks at the Noto Peninsula and many of them are identified petrographically as augite-hypersthene andesite. Thermal conductivity is measured by devidedbar or steady state method. Error of our apparatus for individual measurement is assured less than 5%. Average of 26 samples is 4.13±0.76 (s.d.)×10^-3 cal/cm. sec. deg.. Elastic wave velocites are determined by ultra-sonic-pulse method. 1 Mc TiBaO3 exciter and reciever are used. Error is estimated less than 3% for langitudinal wave and 5% for transvers wave. Average velocities are 5.47±0.34(s.d.) km/sec and 3.30±0.18(s.d.) km/sec for longitudinal and transverese wave, respectively. Average density and porosity are 2.62±0.06(s.d.) gr/cm³. and 2.03±1.20(s.d.)%, respectively. Relation between thermal conductivity and elastic wave velocity is discussed based upon solid-state physics. As a result, phonon conductivity of present samples has an approximately linear relation with velocity as Kph=1.13×10^-8×W, where W=3^1/3(1/Vp³+2/Vs³)^1/3. Palaeomagnetism at the Noto Peninsula is also studied for the same samples as measured physical properties. Natural remanent magnetization is measured by astatic magnetometer and stability is tested by AC-demagnetization method. Conclusions are as follows ; Anamizu formation (about 2.5×10⁷ years ago) was formed under geomagnetic reversal field: Yanaida formation (about 2.0×10⁷ years ago) and Kurosaki andesites (about 1.0×10⁷ years ago) were formed under geomagnetic normal field.

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