38 



THE PRE-CAMBRIAN ROCKS OF MOZAMBIQUE, [vol. lxxi\\ 





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(b) The Ampwihi Crossing:. 



Almost due west of Mozambique Island, at a distance of 

 42 miles from the sea, the military road from Mosuril to 

 Xampula crosses the Ampwihi River, the chief tributary of the 

 Monapo. Near the crossing (see figs. 4 & 5) a Avelcome diversion 



from the monotony of biotite-gneiss is introduced by the appear- 

 ance, in successive belts from north-west to south-east, of horn- 

 blende-gneiss, amphibolite, crystalline limestone, amphibolite, 

 pyroxene-granite, and hornblende-gneiss, the whole series being 

 penetrated by numerous dykes of graphic granite and by one or 

 two coarse-grained clvkes that carry large crystals of magnetite 



