The floral sequence from the Late Miocene to Pliocene in the southwestern Japan-The extinction of the Miocene element and modernization of plant species

研究了日本西南部晚中新世至上新世的花序列。对东海群进行了古植物学调查。东海群的花卉序列分为四个层次。地平线1：三叶松植物群（晚中新世）。德口瓷粘土组和濑户瓷粘土组产生了这种植物群。地平线II：伴随中新世元素的植物区系，在已灭绝的属中不存在。（中新世晚期至上新世早期）Kasahara-cho的Toyooka组、Hutto组下半段和Toki砂砾组发育了该植物群。出现了以下中新世元素：三叶松、原柳杉、白桦、石竹、原柳杉、白杨。地平线III：繁盛时期的水杉植物群。（上新世晚期）年龄组的下部产生了这种植物群。地平线4：绝迹时代的水杉植物群。（早更新世）该年龄组的上半部分产生了这种植物群。这些结果表明，在中新世末期存在灭绝事件，在上新世有一定的灭绝阶段。

The floral sequence form the Late Miocene to Pliocene in the southwestern Japan has studied. The paleobotanical survery about the Tokai Group has carried out. The floral sequence of the Tokai Group is devided following four horizons.Horizon I : Pinus trifolia flora (The Late Miocene)The Tokiguchi Porcelain Clay Formation and Seto Porcelain Clay Formation have yeilded this flora.Horizon II : The flora which accompanies with the Miocene element and is absent from the extinct genus. (The Latest Miocene to early Pliocene)The Toyooka Formation, lower part of Hutto Formation and Toki Sand and Gravel Formation at the Kasahara-cho have yielded this flora. The following Miocene elements occur ; Pinus trifolia, Paliurus protonipponicus, Parrotia pristina, Fagus stuxbergii, Liquidambar protopalmata, Populus sanbonsugii.Horizon III : the Metasequoia flora in flourish age. (The late Pliocene)The lower part of the Age Group has yielded this flora.Horizon IV : The Metasequoia flora in wxtinct age. (The early Pleistocene)The upper part of the Age Group hs yielded this flora.These results suggest there are the extinct event at the end of the Miocene and some stage of extinction in the Pliocene.