Abstract
The Kissawa Formation deposited during the Shimosueyoshi Transgression, ca 150, 000-ca 130, 000 FT y.B.P., is subdivided into six local pollen assemblage zones at Saigato, namely from the lower Ka-I, II, III, IV, V and VI, based on the occurrence of the tree pollen with a high value. Macro-plant remains which are mostly seeds and fruits occur commonly from the upper Ka-I to the Ka-V. Specific compositions of the plant fossil assemblages change conspicuously in two horizons, i.e. the upper Ka-I and the boundary between the Ka-V and the Ka-VI. During the zones of the upper Ka-I to the Ka-V, such warm temperate to sub-tropic elements as Lagerstroemia, Sapium sebiferum, Melia azedarach, Aleurites cordata, Ehretia dicksonii and Buxus, and the temperate elements commonly distributed in Japan coexist constantly. The temperate trees of Ulmus and/or Zelkova predominate in the lower Ka-I of the initial layer, and those of Cryptomeria, Alnus and Picea in the Ka-VI are predominant. Because of this, it is assumed that the climatic condition during the Shimosueyoshi Transgression is similar to that of the present at least.
