Shikiyama Formation

Coherent formation
middle Eocene
Correlation: Segami Formation

Sedimentary facies: Marine
Depth of water: Shallow
Lithofacies: Mudstone, Sandstone

Upper limit: Conformity (Toishi Formation)
Lower limit: Conformity (Fukuregi Formation)

Shimoshima Group
[ Upper ]
--------------
Toishi Formation
--------------
Shikiyama Formation
--------------
Fukuregi Formation
?--?--?--?--?-
[ Lower ]

------ Conformity, ~~~~~~ Unconformity, ~~~--- Local unconformity, '''/,, Interfingered, :::::: Fault, /--/-- Thrust, +__+__ Ground surface, ?--?-- Unknown

Distribution: Amakusa-Shimoshima island, Amakusa city, Kumamoto pref.; Gesu island, Ushibuka town, Amakusa city, Kumamoto pref.
Distribution: Satsukiura seashore, Gesu island, Ushibuka town, Amakusa city, Kumamoto pref.; Mount Gongen, Ushibuka town, Amakusa city, Kumamoto pref.
Fossils: Foraminifera, Calcareous nannofossils
Fossils (Bivalves): Venericardia mandaica, Venericardia nipponica, Crassatella hataei
Fossils (Pteropods): Limacina canadaensis, Limacina pygmaea, Limachina sp., Praehyalocylis annulata

Ando et al. (2009) Jour. Geol. Soc. Japan, vol.115, no.4, pp.187-190 DOI