Abstract
It is well known that the Plio-Pleistocene marine sediments in the Boso Peninsula, namely the Kazusa Group, are remarkably thick and continuous. Many investigations on the stratigraphy and the fossils contained within them have been made in detail. The age of the Kazusa Group has recently become clear by means of some biostratigraphic and geomagnetic works.
On the other hand, the Miura Group distributed over the Tama Hill adjacent to the Boso Peninsula has been poorly investigated. It was believed that the age of the Group was the Late Pliocene. In this paper, the writers described the stratigraphy and the geologic structure of the Miura Group in addition to the review of previous works on the Plio-Pleistocene formation in the Southern Kanto region. The results must offer some data on the restoration of the paleo-geography of this area.
(1) An indistinctive anticlinal structure was found about the upper reach of the Tsurumi River. It seems that the structure is based on the original sedimentary basin structure.
(2) The sedimentary facies of the Miura in the western region of the Tama Hill are characterized by the deposits of relatively shallow sea. In the lower part of the Miura, there are six sedimentary cycles due to the osillation of the sea level of the time.
(3) From some plant fossils, such as Metasequoia, Juglans, the age of the Miura is estimated to be the Early Pleistocene.
