Tertiary Formations in the Yuya-wan (bay) District, Southwest Japan, with References to the Tertiary Geologic History of West Chugoku

This paper treats of the problems concerned with the geology of the Cenozoic strata developed in the Yuya-wan (bay) district of West Chugoku, the Inner side of Southwest Japan. On the basis of the data obtained through his study the writer summarizes the stratigraphy and structure of this district, and gives the correlation among the Tertiary formations of the Saikai, in which the Yuya-wan district is included, Setouchi and San-in sedimentary provinces. As a result of the study, the writer remarks the Mid-Tertiary geologic history and paleogeography of West Chugoku.