The Kavirondo series rocks are developed around Busia, Nambale, and Butula while the granites dominate the northern parts of the county. The northern part of the central region features granitic outcrops, which is essentially part of the peneplain and is characterized by the presence of large granitic hills such as Amukura and Chelelemuk. The Southern part is covered by a range of hills which run from the northeast to the southwest culminating at Port Victoria, forming a very conspicuous topographical feature. The southernmost part of the county is covered by the Yala Swamp that that is down warped area associated with the formation of Lake Victoria.
The Kavirondo Series Rocks