| Ryugase Group | |
|---|---|
| Stratigraphic range: Late Santonian- Early Campanian ~ | |
| Type | Geological formation |
| Overlies | Yezo Group |
| Lithology | |
| Primary | Mudstone |
| Location | |
| Coordinates | 47°12′N 142°30′E / 47.2°N 142.5°E |
| Approximate paleocoordinates | 51°54′N 130°00′E / 51.9°N 130.0°E |
| Region | Sakhalin Oblast |
| Country |  Russia |
| Extent | Sakhalin Island |
  Ryugase Group (Russia) | |
The Ryugase Group is a geological formation on Sakhalin Island in far eastern Russia whose strata date back to the Late Cretaceous.[1]