1. A regime of dunes.
2. A slow transgression causing a long marshy period, during which numerous plants whose remains are found lived in the period.
3. A slow regression.
4. A rapid transgression (grey loam).
5. A slow regression (clayey white loam with traces of roots).
6. A transgression (white loam).
7. Establishment of a new dune regime.
In the Chari basin east of Lake Tchad are the remains of fish and shells, and also small pebbles of sandstone and chalcedony, which are not local, but must have been brought from the mountains of Tibesti by the rivers Egnei and Toro when their current was much stronger than at present. In Senegal, south of the 15th parallel, the present dune sands are underlain by an alluvial soil, indicating moister conditions preceding the present climate. There is no means of dating the moist periods indicated by these phenomena, but it is reasonable to correlate them with the former extension of the central African lakes.
Passing south to the Kalahari, we find evidence of a number of moist stages separated by drier intervals, but they can apparently be grouped into two main Pluvial periods, separated by a long interpluvial with steppe-like conditions. One at least of these Pluvial periods must be correlated with the former immense extension of Lake Ngami and the Etosha Pan.