The present paper is the research report for the Kamitakatsu Shell-midden Site in Tsuchiura City, Ibaragi Prefecture, Japan. The research was carried out to recover information about the subsistence activities, especially fishing activities, of the Jomon shell-midden people (prehistoric hunter-gatherers in Japan). The research also aimed at investigating the pattern of exploitation of environmental resources. But before describing the excavation data and analysis results, some explanation is necessary about one of the environmental phenomena of the Jomon Age, one which is closely related to the purpose of the present research.

The Kamitakatsu Site is located almost in the center of the Kanto Plain (Fig. 1). It is generally agreed that the geographical and geomorphological features of the Kanto Plain changed during the thousands of years of the Jomon Age. The most distinctive changes were the transgression and regression of the sea which accompanied changes in sea level.

As to sea level changes, there are many unsolved problems, especially in regard to cause and degree. It still is not clear how much land sinkage and glacial eustasy influenced these phenomena. As to the greatest transgression during the Jomon Age in the Kanto Plain, Togi (1926 a, b), Sakazume (1942) and Esaka (1943) estimate that it was roughly along the present ten meter contour. This estimate is based on the distribution of the Jomon shell-midden sites (Fig. 2). On the other hand, Hasegawa (1966 a, b, 1967 a, b, 1968) and Wajima et al. (1968) studied the highest marine facies by analyzing the diatom assemblages in core samples from alluvial lowlands near shell-midden sites and estimated that the highest sea level was between zero-six meters above the present sea level.

Besides the above-mentioned problems, there are many other unsolved problems concerning sea level changes. But it is certain that the sea level went through several changes during the thousands of years of the Jomon Age. This means that the shore line changes with time, and, accordingly, the life-environment of the Jomon shell-midden people probably changed with it. It is assumed that changes in shore line most affected the exploitation of shore and marine resources, i.e. fishing activities.

In short, the faunal and floral food remains discovered in shell-midden sites are closely related to the parts of the environment exploited by a given society. This indicates the significance of analyzing various types of data obtained from the shell-midden deposits for an understanding of the relationship between man and environment.