Miyazakibana is the distribution of strata of the Lower Oya Formation of Kuchinotsu Group (the Quaternary Pliocene Period).
The Oya Formation consists of fluvial-delta deposit, and it is partially a lake deposit. (Otsuka and Furukawa, 1988. Otsuka et al., 1995.) The gravel layer contains quartz, chert, schist, and granite, and it is considered to be originated from the Kuma mountain terrain. You can observe the gravel at the seashore.