Pollen flora of the middle-upper Holocene at OH94 drilling samples from Lake Hane has been studied and correlation of pollen zones and subzones to those of the Lake Shinji was examined (Onishi et al. 1990).13;
The K-Ah volcanic ash is identified in the Cyclobalanopssis-Castanopsis Pollen Zone (In the OH94 drilling samples，the K-Ah volcanic ash is identified at GL.-18.54m). As a result，we estimated the base of the Cyclobalanopssis-Castanopsis Pollen Zone occurred before about 6300 y.B.P..13;
Therefore, we argued these periods' validity in terms of sedimenyary velocity and the correlasion of pollen zones. We clarified that the base of the Cyclobalanopssis-Castanopsis Pollen Zone was established before 6450 y.B.P.13;
The vegetation around the Lake Hane at every pollen zone was evaluated.13;