THE EAST AFRICAN SEQUENCE 



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In the case of the volcanic history there are probably 

 five main divisions, three of plateau eruptions and two of crater 

 eruptions. The succession of lavas poured forth appears at first 

 to agree with Richthofcn's theory of the volcanic rock sequence. 

 The plateau -eruption lavas followed one another in the order 

 — trachyte, andesite, and basalt, and this succession appears to 

 support Richthofen's hypothesis. But if we consider the crater 

 eruptions, no definite succession occurs. In these, trachytes 

 occur after andesites as well as before them, and basalts at the 

 end of the series as well as at the besfinninsf. 



