Abstract
Lithostratigraphical and tephrostratigraphical study was carried out on the Kazusa and Shimosa Groups, which are the Middle to Upper Pleistocene around Kongochi, middle part of the Boso peninsula Japan. This paper presents the detailed geological map and cross sections. The Kazusa and Shimosa Groups in this study area have a northeast-southwest strike and a gentle dip to northwest. The dip has the ranges of 0.3°from 4°which is lightly continuously towards the upper formation. In addition, the formation around Osawa, located at the east part of the study area has slight dip, and swollen up structure as well. Basically, every formation stacks conformably in the study area, except that only the Kioroshi Formation unconformably overlies the underlying formations.
