| Toyonishi Group | |
|---|---|
| Stratigraphic range: Tithonian to Lower Hauterivian | |
| Type | Group |
| Sub-units | Kiyosue Formation, Yoshimo Formation |
| Underlies | Toyora Group |
| Overlies | Kanmon Group |
| Thickness | 300–900 metres (980–2,950 ft) |
| Lithology | |
| Primary | Mudstone, Sandstone |
| Other | Siltstone, conglomerate, limestone |
| Location | |
| Region | Shimonoseki City, Yamaguchi |
| Country | Japan |
| Type section | |
| Named for | Toyonishi-son (Village) |
| Named by | Matsumoto, 1949 |
The Toyonishi Group is a group of Mesozoic rock strata in Japan, and was originally named by Tatsuro Matsumoto in 1949.[1] It distributes in the southern half of Shimonoseki City, Yamaguchi Prefecture, southwest Japan, and deposited during the Uppermost Jurassic-Lower Cretaceous along the East Asian continental margin. [2]