Abstract
Orthoquartzite gravels were found from the conglomerates of the Osaka Group, in the Uji Hills, Kyoto Prefecture. The conglomerates are mostly composed of chert gravels (more than 70%), accompanied with gravels of vein quartz, acidic pyroclastic rock, quartz schist, schale, granite, quartz porphyry and sandstone. Orthoquartzite gravels are rarely found. High rounding of orthoquartzite gravels in comparison with the other gravels suggests that they are reworked gravels.
