On the southeast of Hiroshima Prefecture, several kinds of granitic rocks and rhyolites belonging to the Upper Mesozoic are widely distributed.
The writer has classified the granities into four types according to their petrological features and geological relations, and has distinguished three bodies of rhyolites, namely,
granites: (1) the Mannari type (2) the Ashida type (3) the Hirotani type (4) the Mikawa type
rhyolites: (1) the Toyosaka rhyolite (2) the Joge rhyolite (3) the porphylitic rhyolite
Among these bodies, it has been made clear that the Mannari type granite is the oldest one and older than the rhyolites as well. This fact indicates the presence of granitic activity before the eruption of at least some members of the so-called “Takata rhyolite”.