キーワード：関東平野西縁，仏子層，花粉化石，鮮新-更新統．

---

---

Fossil Pollen Assemblages of Lower Part of Bushi Formatiom, Kazusa Group in Iruma City, Saitama in Central Japan

NIREI, Takashi
Saitama Museum of Natural History, Nagatoro, Chichibu-gun, Saitama 369-13

Abstract
　　　 Pollen analytical studies were conducted on the first member of Bushi Formation in lruma City. The fossil pollen assemblages were characterized by Picea, Metasequoia-Glyptostrobus, Pseudolarix, Fagus and Quercus(Lepidobalanus). Paleovegetation can be presumed to be the coniferous forest and the deciduous broad-leaved forest of the cool temperate zone level. Climatic condition was cooler or slightly cooler than that of the present. Paleoenviroments of upper part of FT site was changed from marine condition into freshwater condition.
　　　This part of Bushi Formation corresponds to the lower part Metasequoia Zone of the Osaka Group in Kinki region, South-western Japan. It was clarified here that the disappearance process of the Metasequoia Flora was similar to the Osaka Group.