On-Ys Tephra
Abbr.: On-Ys, YsS
Invalid synonym: Ue (Upper), Y-Pm, S-2 (Inadani valley, Lower)
------ Conformity, ~~~~~~ Unconformity, ~~~--- Local unconformity, '''/,, Interfingered, :::::: Fault, /--/-- Thrust, +__+__ Ground surface, ?--?-- Unknown