Fossil Sassafras hitherto reported from several formations of Lower Cretaceous to Pliocene in Japan and adjacent land seems to show the most extensive development in Miocene deposits.
Fukui plant bed newly discovered at Fukui, Nagahama-chô, Hamada City, Shimane Prefecture belongs to the lower-most part of the Kokubu group, the lowest division of the Hamada Tertiary.
The plant bed must be, stratigraphically and paleontologically, of pre-Daijiman, namely early Middle to Early Miocene.
A new species of Fukui flora, Sassafras Yamanei IMAMURA, will be described below.