Hiwegi Formation
| Hiwegi Formation | |
|---|---|
| Stratigraphic range: Early Miocene ~ | |
| Type | Formation |
| Unit of | Rusinga Group |
| Sub-units | Kaswanga Point Member
Grit Member Fossil Bed Member Kibanga Member |
| Underlies | Kulu Formation |
| Overlies | Rusinga Agglomerate |
| Thickness | 57 m (Waregi Hills) |
| Lithology | |
| Primary | volcanic tuffs, clastic sediments |
| Location | |
| Region | Lake Victoria |
| Country | Kenya |
The Hiwegi Formation is a geological formation on Rusinga Island in Kenya preserving fossils dating to the Early Miocene period. The Hiwegi Formation is known for the well preserved plant fossils it preserves, which indicate a tropical forest environment that underwent wet and dry periods. The middle members of the formation in particular indicate a brief period in which conditions were notably dryer with a more open environment compared to older and younger units. Some of the formation's fauna, such as an early ancestor of the modern aye-aye and a chameleon of the genus Calumma, link Miocene East Africa to modern day Madagascar.