The ridges appeared to trend north and south, and to approach the river's bending bed at different angles; their sides were steep, and in places scarped where they fell into the intervening hollows. The valleys conducted many a water to the main drain, and during the wet season they must be well-nigh impassable. At the end of the dries the only green is in the hill-folds and the basin-sinks, where the trees muster strong enough to defend themselves from the destructive annual fires. These bush-burnings have effectually disforested the land, and in some places building timber and even fuel have become scarce. In the Abrus, barely two feet high, I could hardly recognize the tall tree of Eastern Africa, except by its scarlet "carats," which here the people disdain to use as beads. The scorching of the leaves stunts the shrubs, thickens the bark, and makes the growth scrubby, so that the labourer has nothing to do but to clear away the grass: I afterwards remarked the same effects on the Brazilian Campos. We descended the dividing ridge, which is also painfully steep, especially near the foot, and crossed the rolling hollow with its three chalybeate brooks, beyond which lay our destination. Tuckey describes the hills between Boma and Nkulu as stony and barren, which is perhaps a little too strong. The dark red clay soil, dried almost to the consistency of laterite, cannot be loosened by rain or sun, and in places it is hardened like that of Brazilian Porto Seguro, where the people complain that they cannot bury their dead. All the uplands, however, grow grass which is sometimes ten to twelve feet tall, and in places there are shrubs and trees. About Nkulu the highlands are rightly described as "steep hills of quartz, ferruginous earth, and syenite with fertile tops:" rocks and stones are rare upon the plateaux: they are rich enough to produce everything from wheat to coffee, and hardly a hundredth part is cultivated. Thin and almost transparent lines of palms denote the several Banzas on the ridges, and in the valley are rock circles like magnified and prostrated Stonehenges. The "termes arborum" is universal, and anthills form a prominent feature. It has been remarked that these buildings are the most conspicuous architectural efforts of the country, and the Abbé Proyart observes that here more effectually than in any other land man ought to be sent to the ant school. The material is of dark and sometimes black earth as in the Gaboon, and the shape is the umbrella, rarely double or pagoda-roofed. The column may be twelve to eighteen inches high, and the diameter of the capital attains two feet: I never saw, however, a "gigantic toadstool as high as a one-storied house."[FN#28] Nor are the mushroom tops now used as chafing-dishes.