Hiwegi Formation

Hiwegi Formation
Stratigraphic range: Early Miocene ~Burdigalian PreꞒ Ꞓ O S D C P T J K Pg N ↓
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.