On the Manchidani Formation

Abstract

It has generally been accepted that the Manchidani formation unconformably overlies the Osaka group proper in the marginal part of the Osaka basin. But, the writers had begun to have some doubt about the erosional surface beneath the Manchidani formation. As a result of our detailed investigation, the Manchidani formation in the Senpoku Hill was confirmed to belong to the Osaka group itself.Consequently, the Manchidani formation at Manchidani and Hirakata had to be reexamined. The conclusion on the basis of observations at these fields is as follows (Fig. 6).1. The Larix bed at Manchidani and the Pinus korciensis bed at Hirakata (Shinkori) correspond to the horizon between Ma 6 and Ma 7.2. The Syzygium bed at Uegahara and Hirakata correspond to the Ma 8 horizon.3. The Tomistoma bed at Machikaneyama corresponds to the horizon beneath the Syzygium bed.