Based mainly on the results of pollenanalyses of the late Pleistocene deposits in Japan, the vegetational succession was surveyed. 1. We are able to reproduce the vegetation during the Main Würm reasonably by the parallel replacement of the present vegetational zone. This means the vegetation type during the Main Würm can still be found somewhere in Japanese Islands at present. 2. During the inter-glacial period including sub-interglacial stage, warm and cool temperate elements had fluorished with some subtropical extinct species from Japan such as Lagerstroemia near the sea-side areas of the western part of Japan at least. From this fact it may be inferred that the climate at that time was cooler in summer and milder in winter than at present.
Fluvial and marie terraces are well developed along the middle and lower courses of the Kako River. The author classified these terraces into Upper I terraces, Upper II terraces, Middle terraces, and Lower terraces in the descending order, and correlated them as shown in Fig. 4 and Tab. 3. In this paper, the forming condition of Manshoji terraces (Upper I terraces) which are extensively developed and have thin deposits in the middle course of the Kako River is especially discussed, and whether marine terrace exists or not in Kunioka terraces (Upper II terraces) in the lower course of the Kako River is also discussed. The results are summarized as follows. (1) Manshoji terraces are considered to have been formed in the condition that the Palaeo-Kako River and its tributaries flowed in the slightly undulating hills in the state of few supply of gravels from the surroundings. (2) Kunioka terraces are divided into higher and lower terraces. The left bank of the Kumori River in lower Kunioka terrace is considered marine terrace because of containing trace fossils and topography of bars.
A pollen analysis was made on peat material collected from an archeological castle site at Tagajo, Miyagi Pre fecture to elucidate an impact of early historic man on natural vegetation. The sediments subjected to analysis in the Pollen Zone III yield abundant Quercus pollen indicating a temperate forest developed under a warmer climatic condition than that of the present time. Zone II is characterized by a dominance of Fagus pollen and low frequencies of nonarboreal pollen. Increase of Fagus in this zone may be due to climatic deterioration. The age of the boundary between the Pollen Zone III and Zone II was known to be 2500 year B.P. and that between II and I was 1300 year B.P. The Zone I corresponds to the stage of an intensified agricultural activity marked by a sudden decline of the APF values, decrease of such tree pollen as Fagus, Quercus, Alnus, Castanea, Juglans, and increase of NAP i, e, Gramineae, Cyperaceae, Artemisia, Persicaria, Osmunda, Polypodiaceae. It is postulated that intense activities of early historic man had a great impact on the natural vegetation. Alnus and Juglans were burned away to make farmland. Quercus, Fagus and Castanea were cut down for building the ancient castle. After this catastrophic forest destruction, a migration of Pinus into the lowland of the area was detecteble in the upper Part of the Pollen Zone I.