[in Japanese]

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Fossil pollen assemblages of the Holocene sediments in the Kounosu city, Central Saitama Prefecture, Japan, were analysed to divide into four zones of KON-A, B, C and D from upper to lowere. Zone KON-D are subdivided into three subzones of 1, 2 and 3 from upper to lower.
In Zone KON-D, the deciduous broad-leaved forest dominated by Quercus （Lepidobalanus） spreaded. In Subzone KON-D-3, recognized were the deciduous broad-leaved forest with Secondary pine forest and glassland spreaded.
In Zone KON-C, deciduous broad-leaved forest with evergreen forest indicated by Cyclobalanopsis and Cryptomeria spreaded. It means increase of the precipitation. In Zone KON-B, the effect of the vegetation destruction by human impact increased. In Zone KON-A, secondary pine forest and glassland spreaded. while, broad-leaved forest decreased.
We identified Fraxinus platypoda fossil pollen for the first time on Pollenanalytical study in Japan.

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" Scenery geologist " Tetsugorou WAKIMIZU went to study to Europe and America at the biginning of Taishou era of the age of the assistant professor of Tokyo Imperial University Agricultural College. The 49 rock specimens corresponding to the period and the region of his studying abroad were discovered by this investigation. The outline of the geological excurtions to Germany, Italy and Switzerland is clarified based on the rock specimens that Tetsugorou WAKIMIZU has collected, and a part of the history of Japanese geology at the beginning of Taishou era is presented concretely.

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Yamazaki Formation (upper Upper Miocene) is defined in the eastern part of the Miocene Maebashi-Kumagaya Basin, on the north of the Kanto Mountains. The Yamazaki Formation is distributed in the northernmost part of the southern belt of the basin, and conformably overlies the lower Upper Miocene Suwayama and Yagii Formations. The Yamazaki Formation consists of conglomerates with subordinate sandstones and tuff. The depositional facies is probably fluvial to fan. Cobble to boulder sized andesitic clasts are dominant among the pebbles in the conglomerate. The FT age of zircons from the andesitic to dacitic Mikajiri Tuff intercalated within the Yamazaki Formation is 6.5±0.4Ma (Upper Miocene). The Yamazaki Formation, therefore, may be correlated with the Lower Akima Formation, which consists mainly of andesitic tuff breccia and intercalated andesitic lava, occurs in the western part of the Maebashi-Kumagaya Basin.

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The geography at the northern part of Arakawa Lowland consists of the natural levees, remained rivers and back marshes. These natural levees are classified into three groups according to these distribution and shapes ; old natural levee, middle natural levee and new natural levee. Recent formations in this area are divided into nine members ; Kabusou Ⅰ～Ⅳ, Johbusou Ⅰ～Ⅲ. Kabusou Ⅱ～Ⅳ and Johbusou Ⅱwere channel fill deposits consisted of medium～coarse sand and humus silt. Kabusou Ⅱ～Ⅳ were deposited by paleo-Tonegawa rivers.
From the many archeological findings in this area, we believe the ages of the natural levees and remained rivers in this area are the Early, the Middle, and the Late Jomon period.

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