Page "Geography of Africa" Paragraph 6

As a general rule, the higher tablelands lie to the east and south, while a progressive diminution in altitude towards the west and north is observable.

Apart from the lowlands and the Atlas mountain range, the continent may be divided into two regions of higher and lower plateaus, the dividing line ( somewhat concave to the north-west ) running from the middle of the Red Sea to about 6 deg.

S. on the west coast.