M. Fergusson — Notes on Geologij of Tanganyika. 363 



Immediately north of this rhyolite the country begins to rise again, 

 splitting up into small detached hills at first and gradually rising to 

 mountains of quartz-felsite at Moliro's. [" This rock contains fairly 

 large phenocrysts of quartz and orthoclase in a microfelsitic base 

 showing flow structure and in parts also spherulitic structure."] j 



Crossing now to the eastern shore, we find the sandstones 

 continue up as far as the German station of Kasanga, but just north 

 of this they terminate and felsitic rocks again intrude and pi'e- 

 dominate, gi'anite sometimes showing up through the mass. As we 



