In the Volcanic Region 119 
the whole district, and encamped in the neighbourhood of Lake 
Karago, in the province of Kahama. 
The lava crust on which we were advancing originated from 
the volcanic eruptions of comparatively earlier times, but is not 
so old as to have fallen into complete disintegration, as it has 
done in many other parts. Where this, however, has happened, 
the ground has been rendered exceedingly fertile through the 
formation of vegetable soil, and is most industriously cultivated 
by the natives. Skamba after shamba are to be seen in unbroken 
succession, on which bananas, negro millet (mtamd), sweet 
potatoes, maize, peas and beans are grown. In Kahama one 
could clearly discern the detached lava streams and the manner 
in which they had once poured themselves devastatingly over the 
land. 
Spacious caverns formed under the crust of the lava streams, 
and have remained to the present day. We searched around for 
them, and crept into some of them so as to inspect the interiors. 
The entrances mostly lie concealed under shrubbery, and it 
occasionally takes a long time to find an opening. These caves 
served the Wanjaruanda * not seldom as secret lurking-places. 
Even as late as 1906 Captain von Grawert had arrows showered 
upon him from the mouth of one of these caves whilst engaged 
on a punitive expedition in those parts in consequence of 
rebellious conduct. The hostile demeanour of the people has 
now given way to one more peaceable, and since then these 
cave formations have but rarely been used as entrenchments. 
Having separated again from Grauer, who proceeded on his 
way to Lake Kiwu, we crossed a few heights and made some 
steep descents on our way to the old lava streams, which were 
visible far away. The journey was, if possible, still more diffi¬ 
cult and disagreeable than that of the previous day, as the lava 
had in parts congealed in a most serrated and jagged fashion. 
The sharp edges and pointed ends were particularly disastrous 
to the carriers. Their wounds had to be treated, and this delayed 
the marching to such an extent that the caravan became quite 
* Inhabitants of Ruanda. 
