Outline of the Plant Remains from the Quaternary Deposits in the Ishikari Plain, Hokkaido

Abstract

In the Ishikari Plain, the Quaternary sediments are extensively distributed. We have investigated them since 1957.In this paper, we report the some plant remains we could obtain until now. The sediments in which the plant remains included are the Dateyama formation in the northern district, the Kakuta formation in the eastern part, the Nopporo formation, the Nishinosato formation in the eastern part, the Nopporo formation, the Nishinosato formation and the Takadai clay formation in the western, the Nittaporo formation, the Shimoabira fomation and the Shiomi formation in the southern district of the Ishikari Plain.Especially, we could obtain remains of Larix Gmelinii from the Nopporo and the Nishinosato formation, and remains of Abies Veitchii and Pious koraiensis from the Nittapporo formation.Abies Veitchii, Pinus koraiensis and Larix Gmelinii are species which are not found in the present flora of Hokkaido. Abies Veitchii and Pinus koraiensis are growing in subalpine regions of Central Honshu, while Larix Gmelinii is growing in Southern Kuriles, Saghalin and Eastern Siberia.The Plant remains discovered from the Quaternary sediments in the Ishikari Plain, indicate that they were growing in Hokkaido at the time. We believe they offer the interesting data on the plant geography.