CLIMATE AND NATURAL HISTORY. 225 
ment of a future maternity, lead a quiet and regular life. 
The doves relax in their cooing, and devote themselves to 
a gluttonous repast on the many seeds which ate now © 
scattered broadcast on the soil. The baobabs shed their 
leaves, and everything once more re-enters the winter 
state of repose and recuperation. 
The rain on the Congo not only falls with considerable 
force and persistence, the downpour sometimes lasting 
continuously for twenty hours, but also seems to possess 
some chemical quality which aids it in disintegrating the 
hard metamorphic rocks, and in forming the deep-red 
surface soil. The action of water, both falling from the 
sky and coursing in torrents down the hills, has largely 
modified the surface in the Congo lands. Strange hollows 
and ravines are scooped out by the rain wherever it finds 
a weak spot, and, after every heavy thunderstorm, the 
water rushing down the hillsides in temporary brooks 
carries with it quantities of the friable soil, and cuts great 
_ channels which in course of time become accentuated and 
deepened till their sides fall in, and thus the mountain or 
hillock is slowly but surely being levelled and the valley 
filled up. Here and there in the hilly cataract region 
great isolated blocks of quartz le about, either washed out 
from the hillside by rain-made landslips, or forming in a 
plain the last relics of a bygone hill that has long resisted 
disintegration. In the bed of the river there are many 
rocks of clay slate. Basalt also enters into the geological 
formation of the country, and on the river above Stanley 
Pool the rocks appear volcanic. Iron is abundant 
throughout the Congo basin—many of the rocks are 
streaked with ferruginous stains—and is known and used 
by the natives, who call it mputo. Neither silver nor gold 
are known by the Congo people. When shown gold by a 
Kuropean they take it for inferior copper. 
Topazes are said to be found near Bolobo, as I have 
mentioned in my account of that place. I have never, 
however, seen any precious stone of any kind in the 
possession of the natives; flakes of mica I have noticed 
among some of their charms. 
Pe 
