Some hollow topographies in Kwanto Plain are found out in three locations, namely, on alluvial sand dune, on the Musashino Terrace and on the Tama Terrace. The writer researched the hollow and the related valley topography in the vicinity of Mt. Kanozan (Tama terrace in Boso Peninsula).
Mt. Kanozan is composed of unconsolidated sand, and the southern edge of this mountain shows a clear escarpment, while the back slope declines gently to the north. And its shape presents cuesta-like topography.
The writer summarized the result of the survey as follows.
1. On the flat surface near the summit, there are several circular or elliptical shallow hollows with about 20_??_200m in diameter, 1_??_2m in depth.
2. The most of the valleys on the back slope of this mountain have flat valley bottoms with certain width at their upper parts where no stream is seen.
3. The change of gradient froze the flat valley bottom to the valley side slope is abrupt, and it seems that the seeae of ground water at the foot of the slope plays a role in widening the valley bottom.
4. The distribution of springs suggests that the ground water is sustained in consolidated sand or thin clay lenses caused by the differences of the original sedimentary conditions.
5. The valley head forms of this region are classified into five types from the longitudinal and transversal profiles, and it is, assumed that each type of them shows a process in the series of morphological development of valley, and such flat bottom' valleys are originated from the growth of hollows.
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