Appendix C. 
although some specimens present a typical graphic association of quartz with 
microcline. 
In the Lwamutukuza, Muyongo and Fort Portal districts I noticed in the 
gneiss-granitic formation considerable intrusions of diabase rocks of granular and 
sometimes coarse-grained structure. The specimens collected by us never 
contain olivine, nor even the chloritic green pigment so common in the rocks 
of this type in our lands ; characteristic is always the abundance of ilmenite, as 
also the basic felspar often referable to anorthite. 
Thanks to the metamorphosis of the pyroxenes in amphiboles, which may 
be easily followed in its various transitions, some of these diabases pass over to 
epidiorite ; true dimite I did not come across in situ, but believe that it occurs in 
the Kaibo-Butiti district. Conspicuous also, between Fort Portal and Duwona, 
is a thick bed of overlying hypersthene gabbro of coarse structure. 
Palceozoic.- —The formations which represent the Palaeozoic Age follow for 
about 50 miles between Mitiana and Kasiba. Their eastern limit did not appear to 
be very clearly marked, whereas the western is distinctly defined by the granitic 
range which I have described as extending from Kasiba to Muyongo. It is in 
fact against these very escarpments that the palaeozoic formations are inclined. 
The rocks met in the district are sandstones, arkoses, quartzites, quartzite 
breccias and various schists, micaceous or talco-micaceous. All these rocks, whose 
clastic and metamorphic origin is readily recognized in the petrographic 
laboratory, are for the most part coloured a deep red, and correspond perfectly 
to the rocks referred to the Palaeozoic Age, as described by observers in other 
parts of Uganda, as well as in Congoland and South Africa. 
An exact determination of age is too often prevented by a total lack of 
fossils. I think, however, that it may be useful to point out how some of the 
schists met by me greatly resemble analogous formations of the Permian 
Epoch in the Alps, and how, as we proceed westwards, the series seem dis¬ 
tinctly to pass from the sandstones to the schists, thus suggesting a steady 
increase of metamorphism in that direction. 
Recent formations. —These are represented by the concretionary limonite (the 
ironstone of English writers), and by laterite. 
The concretionary limonite is one of the characteristic formations of the 
Lake Victoria region. 
Already on the east shore, and then in a typical manner on the west, in 
the Entebbe district and beyond it, we may say as far as the Ivasiba-Muyongo 
granitic zone, the ground is covered with a concretionary limestone, at times 
pisolitic (pea-like) or vacuolated, always very compact, colour shifting from a 
bright red to a brownish-yellow or dark brown. 
384 
