part 1] 



AXD ASSOCIATED EOCKS OF MOZAMBIQUE. 



83 



(PL X, fia^. 6) as a constant constituent of the sands of the Bwibwi 

 and of those of its tributaries which were examined. Monazite is 

 probably brought down in considerable abundance by the Matupa 

 River and the Potela Mazi ('Tsetse Ply Water'), for in residues 

 4 & 5 the proportion of this mineral is much higher than in 

 the upper parts of the Bwibwi. Monazite has not been found 

 in any of the rocks examined, and as these include the gneisses and 

 granulitic granites of the Elba we Mountains and the Xrassi Basin, 

 it seems probable that the main source of the mineral is to be 

 found in the coarse pegmatites of the region. 



The Sawa sands contain deep-red spinel, which was picked up 

 by Mr. E. J. Wayland in fragments as big as a pea from 

 pockets of gravel occurring in the gorge a few miles above the 



Table X. 

 Heavy Residues from River-Deposits and Crushed Rocks. 



Minerals. 



1 



2 



3 



4 



- 

 o 



6 

 a 



7 

 c 



8 



c 

 a 



9 



c 



a 



10 



c 



a 



11 



12 



13 



14 



a 



15 j 

 c 1 



Magnetite , . 



c 



c 

 a 



c 



c 



c 



c 

 a 

 r 



c 

 a 

 r 



r 

 a 



Ilmeiiite ... 



a 



a 



a 



a 



a 



a 

 c 



V 



a 



Garnet r 



r 



r 



r 



c 



r 



r 

 a 



c 

 c 

 c 



a 

 r 



r 



a 



c 



c 

 r 



r 



— 





Zircon a 



a 



a 



a 



a 



a 

 r 



c 



a 



a 



a 



r 





Rutile 



r 



r 



r 



r 



r 



c 



r 



r 



r 





Monazite 













c 



c 

 r 





- 



Spinel r 



r 



r 



r 



r 













Sphene 



r 



r 



r 

 r 



r 

 r 



r 

 c 



r 



a 



— 



8 





" 



Apatite 



r 



r 



c 



1 



a 



c 



c 



[a = abundant ; c = common ; r = rare. J 



River-Deposits. 



1. Sawa River, between Base Camp and village. 



2. Bwibwi River, below its contluence witb the Sawa. 



3. Do. below its contluence with a tributary from Mount Tipwi. 



4. Matupa River, at the mouth of the Matupa Pass. Ribawe Mountains. 



5. Bwibwi River, above, its confhunce with the Potela Mazi ("Tsetse Fly 



Water'). 



6. Xrassi River. 



7. Do. 



8. Monapo River, near Mpera. 



9. Do. below the crystalline limestone near Mount Tibwi. 



10. Ligonia River, near Fort Ligonia. 



Hocks. 



11. Gneissose granite. Sawa (contains also epidote ; r.). 



12. Do. Etipoli Hills (contains also pyrite and mispickel ; r.). 



13. Hornblende-gneiss. Ampwihi (contains also epidote ; c). 



14. Granulitic granite, Mpera, Monapo Uiver. 



15. Augite-granite, below Ericola, Xrassi Basin. 



G 2 



