To the geologist the country between the coast and Stanley Pool is best studied along the river. The first low hills approach near to the mouth of the river, which is about seven miles wide, and devoid of a delta; the next step in the plateau occurs at five miles west of Mboma, fifty miles from the coast, where the tops of the ‘hills’ are from 500 to 700 feet in height. There we find a red clay yielding copal above granitic rocks. The banks grow steeper and the river narrows, until at Vivi the first serious obstacle is met, the plateau level being about 1,700 feet, and the river about 600 yards wide. Just above this is the fierce Yelala Cataract; indeed, nowhere can you properly speak of falls; a drop of fifty feet, which would be a fine scene on an ordinary river, is almost disregarded by the Congo. The bed of a cataract must be of very hard rock, and down this inclined plane, the river, nipped tightly by the hills, rushes with fearful velocity, leaping in mad waves, foaming and raging at its rocky obstacles. In some of the milder cataracts it rushes down a swirling mound of water, which projected into the quieter low level at the foot of the cataract, races on as a heap of waters for nearly half a mile, before it consents to swirl about at the lower level. Fierce up currents run along the shore at such points, which would draw boats or canoes into the swirling current, while along the edges of these counter-currents are great whirlpools, giving way to each other, disappearing, and breaking up into ‘caldrons,’ the whole surface heaving and seething. In a creek three miles below the Ntombo Cataract we have watched this heaving. The water would flow outwards from the creek, then meeting the impulse of a fresh heave, would flow back until it would remain stationary for some twenty seconds, often two feet higher than what it was a minute ago. This flows backwards and forwards in the creek, recurring every two minutes or minute and a half.
A LOAD.
At Vivi the country is much eroded, granitic rocks, schist, mica, gneiss, and quartz are exposed. The hill-sides are rock strewn, and the country is wild and desolate, covered with weak grass and stunted gnarled trees. In the more level spots rich soil has collected, and the natives cultivate there their cassava, ground-nuts, etc. This is the nature of the country for the next fifty miles. Near the river a chaos of hills, further away rolling plateau, covered with strong grass and stunted trees. The tops of these nzanza, by Mr. Stanley’s careful survey, vary but fifty feet over stretches of forty miles. Above Isangila limestone crops up with slaty rocks, the main level near the river is lower, and traversed by straight ridges of hills running parallel with the coast, and from five to ten miles apart. Clear of the limestone, the country is once more a torn plateau, slate and shale abound, until at 200 miles from the coast occurs a very marked step of 700 feet. Here the country is from 2,300 to 2,500 feet above the sea, and continues so, the rock being a red or purple sandstone. Several higher ridges cross the country as you near Stanley Pool, cut abruptly by the gorge of the river, and continued on beyond. Stanley Pool is a widening out of the river in a weak point among the hills, which marks the head of the cataract region, the water level being about 1,000 feet above the sea. The plateau country continues for a further 150 miles, when hills disappear, and the main level appears to be about 1,100 feet above the sea. From Irebu, 250 miles above the Pool, to Stanley Falls, the banks are forest-clad. The country then divides itself into three regions between the coast and Stanley Falls. The lower river 100 miles, cataract region 200 miles (nearly 300 miles in winding course), the upper river 1,060 miles. Or coast level fifty miles, plateau level 400 miles, central level 900 miles, of which 800 miles are forest-clad banks.
The cataract region is the obstacle that has kept so long secret this great highway; but that passed, on the upper river there are 1,100 miles of unimpeded navigation, while the affluents are estimated at 2,000 miles; beyond the Stanley Falls stretch another 2,000 miles of riverway. Two of the affluents have been explored, and on each was found a lake, while the natives at the mouths of other affluents speak of lakes. It is highly probable that further explorations will reveal other lake regions, all available to the steamers and boats on the upper river.
Communications interiorwards are certain; but between the coast and Stanley Pool everything must be transported on men’s heads, until there shall be a railway. The roads are mere footpaths over the hills from town to town; while the tall thick grass is so strong that it must be hoed up and the bushes cleared before any wheeled carriage could be used. Then again the country is so torn, and streams in their deep gorges so abundant, that travelling is very largely a series of ascents and descents.
CHAPTER III.
Vegetation, Climate, and People.
The vegetation is very varied in the rock-strewn sides of the ravines, in the granitic and quartzose regions it is very bare and weak. But where the plateau level has been less disturbed, the thick maxinde grass (x = sh) shows the richness of the soil; while the carefully tended farms near the towns, beautiful with the rich green of the ground-nut, thickly tangled with sweet-potatoes, or jungled with cassava bushes, show what can be done with the soil, by clearing and a little scratching with the hoe.
