the approach to the great central plateau of africa is marked by the west-central highlands, a series of irregular escarpments and cuestas parallel to the coast at distances ranging from 20 km to 100 km inland as tala mugongo (), chella and vissecua (). the cuanza river divides the mountain zone into two parts. the northern part rises gradually from the coastal zone to an average elevation of 500 meters, with crests as high as 1,000 to 1,800 meters. south of the cuanza river, the hills rise sharply from the coastal lowlands and form a high escarpment, extending from a point east of luanda and running south through namibia. the highest peak is mount moco (), and the escarpment is steepest in the far south in the serra da chella mountain range. in benguela province other high points are loviti (), in 12° 5' s., and mt. elonga (). south of the cuanza is the volcanic mountain caculo-cabaza ().