SUMMARY 



OF THE GEOLOGICAL OBSERVATIOXS MADE IN 

 UGANDA AND IN THE EUWENZORI RANGE 

 DURING THE EXPEDITION OF H.R.H. THE 

 DUKE OF THE ABRUZZI, 



BY 



ALESSANDRO EOCCATI. 



L— UGANDA. 



Overlooking for the present the recent surface formations of concretionary 

 limonite and of laterite, that part of Uganda which was traA'ersed by H.K.H. 

 the Duke of the Abruzzi's Expedition was found to be for the most part 

 •constituted of the crystalline rocks which form the archsean plateau of Central 

 Africa. A not inconsiderable tract, however, of the region traversed is covered 

 with sedimentary formations referable to the Palaeozoic Age, and in the inter- 

 mediate neighbourhood of Fort Portal there is an apparently limited zone in 

 which the crystalline rocks are overlaid by recent volcanic formations, 

 represented by stratified tuffs which I take to l)e of sul)aqueous origin. 



Arckcean. — On leaving Entebbe in the direction of the west, archsean 

 crystalline rocks are followed from the shores of Lake Victoria nearly to 

 Mitiana. Here begin to appear the palaeozoic formations, which, interrupted 

 here and there by out-cropping coarse-grained granite and pegmatite, extend to 

 within a few miles of Kasil:)a, where they suddenly disappear altogether, their 

 place ])eing taken by the crystalline rocks, which continue westwards without 

 further lireak and thus constitute the whole of the Euwenzori Range. 



The archaean rocks are represented l>y ìiìiay-schists, gneiss, and granites (always 

 associated with numerous quartzites), amongst which are here and there noticed 

 intrusive greenstones, and seams of pegmatite, microgranitc, etc. 



382 



