284 
THE LUMBWA AND ELGON CAVES 
tain the waters of Lake Victoria extended far to the north- 
east and covered what is now Bnsoga and Bukedi country 
and extended into the Karamojo plains north of the mountain. 
If this is correct we have the water necessary to excavate 
caves, but at first sight it seems unlikely that the waters of this 
extended sea were more than a few hundred feet above their 
present level, and we have caves on Elgon some 2000 feet above 
the ordinary level of the surrounding terrain, so that the 
question then becomes ‘ Can the mountain have risen ? * It 
may have risen to some extent, for the following reason : At 
one period in its history there was evidently a great convulsion, 
for the eastern wall of the mountain is seen to be torn asunder, 
and a mighty stream of lava issued from the breach and flowed 
eastward for many miles over what is now the northern part 
of the Uasin Gishu Plateau, and formed a ridge which now 
separates the watershed of the Turkwell and^Nzoia rivers. 
Judging by the way the region in the vicinity of the Lake 
is faulted, there can be no doubt that the crust of this portion 
of the earth is in a condition of stress, and it is quite possible 
that the removal of several million tons of material by the 
eruption above referred to so lightened the mountain mass 
that it rose owing to reduction of local stress. The drying 
up of what may be termed the north-east arm of the lake 
would also further relieve the pressure on the crust in this 
area. These causes would, however, be unlikely to produce 
movement to the required extent. 
On the north side of the alluvial plain between Muhoroni 
and Kibos there is a gigantic escarpment running east and 
west composed of ancient gneisses and schists, and rising 
nearly 2000 feet above the plain. High up on this escarpment 
there are a number of caves : one was the scene of a fight 
during the Nandi expedition about 1901, and it was said to 
be big enough to hold 200 head of cattle. 
These caves have recently been explored by Mr. P. L. 
Deacon, District Commissioner, Nandi, and his description 
leaves little doubt that they are what is called fault-caves. 
We have on the Nandi Escarpment a mass of metamorphic 
rocks which are traversed by granitic dykes ; a fracture 
in the earth’s crust which runs from the Maragoli Hills north 
