Ash and cinder cones.

These are small steep sided hills usually less than 200m in height formed by very violent eruption. Violent eruption brew lava into very many fragments of various sizes with ash being smaller than cinder. These are blown in the atmosphere and later laid down around the central vent in layers of ash and cinder. Each layer represents a phase in eruption. It’s the accumulation of these layers of ash and cinder that forms these hills. Such hills frequently occur in groups and near large volcanoes. Examples of such are Teleki, Likaiyu, Nabuyatom and some are found south of L. Turkana in Kenya. In Kisoro they include Muganza. Sagitwe, Bisalo, etc.