Abstract
1. The Uonuma Group (2250m+) at Oguni Region, can be divided into four parts. It has concordant synclinal structure with Neogene system, which axis runs NNE-SSW through the center of the Oguni basin.
2. The sedimentary facies of the Uonuma Group are shown in Fig. 1. The thirteen key horizons (SK 010-SK 130), which are made up of several kinds of tuffite beds, are proved to be remarkable for their correlation.
3. As the result of analysis of fossils from Uonuma Group (Fig. 2, Table 2) it is assumed that the paleoclimate during the stage of the Uonuma Group gradually changed from warm to cool, and that Metasequoia flora may have been extinct by the top stage of the Middle part. The sedimentary environments are considered to have changed from marine water (the Lowest stage) to brackish water (Lower to Middle stage) and then to fresh water (Upper stage).
4. In conclusion the Uonuma Group may be roughly correlated to the Osaka Group in the Osaka District.
