Progress in the tephrostratigraphy in Kantô and Kinki for years made it possible to correlate the Plio-Pleistocene Kazusa group in South Kantô with the Osaka group and its correlatives in Kinki. In this paper the writer tried to correlate both groups by fossil elephants, fossil plants and paleomagnetic polarity of the deposits. Both Kazusa and Osaka groups lying below the biozone of Elephas naumanni yield Stegodon orientalis in the upper part. On the other hand, Stegodon shodoensis akashiensis is reported from the Lower part of the Osaka group, and molars of Parastegodon cf. aurorae which is an allied species of S. akashiensis were found at the middle and upper horizon of the Umegase formation (middle part of the Kazusa group) in Tama Hills. Moreover, in the Boso Peninsula the Umegase formation yields some specimens of Parelephas proximus which is thought to be closely related with Elephas shigensis from the Lower part of the Osaka group. Based upon these facts the correlation between the Kazusa and the Osaka groups is shown in the Table 1. As for the plant remains the Lowest part of the Osaka group is characterized by many species belonging to the Metasequoia flora. In South Kanto the Metasequoia flora has been reported from several horizons of the Kazusa group in Tama Hills which are correlated with the Umegase (or partly Otadai) horizon in Boso. According to the ONISHI's investigation into the pollen flora of the Kazusa group in Boso the group is divided into six pollen zones, and the correlation by the pollen zones of the Kazusa group with those of the Kinki district was carried out (Table 2).
Paleomagnetic stratigraphy was investigated through successive measurements of DRM of the late Cenozoic formations of Boso and of NRM of the volcanic ash layers interbedded in the Osaka group and its correlatives together with fission-track dating of some ash layers. The boundary between the Brunhes and Matsuyama epochs is correlated with the middle horizon of the Kokumoto and the lowest horizon of the Upper part of the Osaka group. The Jaramillo event corresponds either to the middle Kokumoto or to the upper horizon of the Lower part of the Osaka group. Moreover, the Olduvai event is correlated with the middle horizon of the Umegase and with the boundary between the Lower and Lowest of the Osaka group. The correlation by the paleomagnetic polarity is shown in Table 3.
