8 
MIOCENE BEDS OF VICTORIA NYANZA 
patch of the upper series on the left bank of the Kuja, near the 
Ogo ford, 15 miles inland from the lake. Here the grey shales 
and clays are identical in character with the typically unfossili- 
ferous upper beds ; they occur on the same line of strike as 
Kachuku and approximately at the same level and they exhibit 
the same dip, viz. 8° N. by W. 
It is a remarkable instance of the persistence of freshwater 
forms that although the vertebrate remains clearly indicate 
the Lower Miocene age of these deposits the fossil shells without 
exception belong to species which are still living in Equatorial 
Africa. Ampullaria ovata, however, is the only one of these 
Miocene shells that occurs in the Victoria Nyanza at the 
present day. Lanistes carinatus is not found nearer than 
the Tana River, whilst the nearest recorded localities for 
Cleopatra bulimoides are at Mombasa and in the Lake Rudolf 
region. 
Every year a greater area of the fossiliferous beds will be 
exposed, for the heavy rains not only wash away the soft 
black cotton-soil overlying the beds, but the gullies are tem- 
porarily filled with swollen torrents, which scour away the soft 
clays so as to undercut the sandstone ledges, which break away 
into slabs when unsupported. Thus fresh specimens of fossils 
will continually become exposed to view. Dr. Andrews has 
already indicated in his article in this Journal the importance 
of these isolated and scattered bones, and how they can throw 
light upon the early distribution of animals in Africa as well as 
upon the origin of the present fauna. Very valuable results 
may be attained if any visitor to Karungu will turn aside to 
inspect the gullies of Nira and Kachuku and to secure for the 
British Museum any fossil bones or teeth which he may discover, 
noting carefully and photographing the exact bed in which 
they occur. 
