1) We have examined, by the method of pollen analysis, the Yasuda formation that is the deposits of the Shimosueyoshi stage, at Yokoyama, Yoso, Nozaki, Nishiyama and Yukinari in Kashiwazaki Plain in Niigata Prefecture. As the results, Alnus, Quercus, Tilia, Fagus, Cryptomeria, Juglans and Pinus dominated in the Lower Yasuda formation. The central part of the Upper Yasuda formation has no great difference from the Lower Yasuda formation, though the central part of the Upper Yasuda formation might intermingle some more fossil pollen of Tsuga diversifolia type among collection Tsuga than the Lower Yasuda formation did. At the top of the Upper Yasuda formation, Alnus and Tsuga dominated, there were more Abies and Picea contained than at any other place, and Tsuga consisted of the fossil pollen of Tsuga diversifolia type. 2) The Lower Yasuda formation was classified into two parts, upper half and Lower half, because it may be noticed slight difference in the assemblage of pollens, but its boundary is not clear. 3) It was recognized that the paleoclimate in the process of the deposition of the Yasuda fo rmation was getting cooler with the change from the Lower to the Upper; it was warm in the Lower, slightly cool in the central part of the Upper and cool in the top of the Upper. 4) The Yasuda formation deposited in the inland bay in the process from transgression (the Lower Yasuda formation) to regression (the Upper Yasuda formation). 5) Old Sand-dune of Arahama Sand-dune was made up in the process of regression in getting colder in the climate after the age of the deposition of the Yasuda formation. 6) The Lower Yasuda formation may be correlated to the Iwano formation that produced Palaeoloxodon naumanii at the Yoneyama coast. 7) The Yasuda formation may be correlated to the Hirayama formation and the Haranomachi formation in the Takada plain, the Iwano formation at the Yoneyama coast, and the Kuninaka formation in the Kuninaka plain (Sado Island).
Sand beds which mainly consist of massive, consolidated and well-sorted sand are observed along the coast of the Japan Sea and are thought to be Pleistocene dunes. The writers call these dunes the “Ancient Dunes” in contrast with “Recent Dunes” of the Holocene epoch. The Ancient Dunes can be classified into two groups: the older “Ancient Dunes I” and the other “Ancient Dunes II” according to the different ages of formation. The Ancient Dunes I consists of grey, massive and consolidated medium sand, the lower part of which is occasionally aqueous, and is overlying on the middle terrace deposits almost conformably, although partly unconformably. The dunes of this group are found all along the coast of the Japan Sea from North Kyûshû to Aomori Prefecture, the northernmost of Honshû. The Ancient Dunes II consists of pale yollow fine sand with crepe-like texture, which is a characteristic feature of loessy sand. The dunes of this group are distributed at Yasuoka in Yamaguchi Prefecture and south of it while, along the northern coasts they are not found. There is brown weathered clay or volcanic ash overlying the Ancient Dunes I, which may be the equivalent to them in age. The stratigraphic relation between the sand beds of the Ancient Dunes and the terrace deposits or volcanic ash deposits suggests that the Ancient Dunes I and II are correlated to the Riss-Würm interglacial and the Würm glacial stages respectively. They are thought to have been formed the marine regression in glacial ages.