part 1] THE PHE-CAMBRIAN ROCKS OF MOZAMBIQUE. 43 



consist of similar rocks, a fact already observed by Mr. J. T. Last 

 in 1SS7. 1 



The rocks of the Malema Valley are chiefly biotite-gneisses, 

 which become coarsely banded and injected with granulitic peg- 

 matitic veins in the neighbouring peaks. South of Makalia, 

 Mr. E. J. Starey found a number of magnetite-bearing pegmatites. 

 North of Makalia graphite deposits (like those of Nunua near the 

 coast) have been found ; but here again their position in the 

 sequence is obscure. 



Elsewhere to the west of Kibawe, biotite-gneisses, sometimes 

 coarsely banded, sometimes so finely-grained as to become almost 

 schistose, occasionally passing into hornblendic varieties, and in 

 the mountains becoming less foliated, are everywhere the pre- 

 dominant rocks ; as indeed they are throughout the whole District 

 of Mozambique beyond the narrow coastal belt. 



(g) General Sequence and Classification. 



In Table I (p. 42) the sequences of rocks in eight of the better- 

 known .areas are summarized. The implied correlations are only 

 put forward tentatively. It is thought probable that all the rocks 

 of each horizontal series are younger than those of the series 

 below, but it is less probable that all the rocks placed in an}* one 

 horizontal series are of identical age throughout the country. 

 Within these broad limits, however, the evidence seems to justify 

 a classification of the rocks in the following order : — 



Ultra-mafic 

 Dykes. 



Table II. 

 {& itCS - }§ VIII, p. 80. 



Intrusive Contact. 

 /-.,-, , C Biotite- and muscovite-granites. ~\ 



,-. < Graphic granite and other pegmatites. > § VII, p. 70. 



massive pegmatites. ) A ', B . l ° \ s ' e 



1 ff (.Quartz-vems. j 



Intrusive Contact. 



fBiotite-granites. ") 



Granulitic granites, | Pegmatites. ' 



pegmatites, j Pj-roxene-ajranites, adamellites, and ! s VT fi - 



and ] quartz-diorites. j-gvi, p. o/. 



associated rocks. j Rutile-bearing rocks. 



^Granulitic norite. .J 



Intrusive Contact. 

 f Biotite-gneisses and gneissose granites. "1 

 Gneisses and | Hornblende-gneisses. 



as>ociated ■< Amphibolite^. y § V, p. 52. 



rocks. I Garnetif'erous gneisses, granulites, 



[_ and eclogites. J 



Intrusive Contact. 

 'Forsterite-marble and other crystalline") 



limestones ; (including products of > § IV, p. 46. 

 contact-inetamorphism). 3 



Crystalline schists 



and -^ Sediment-gneisses. ^ 



limestones. Quartz- and mica-schists. 



Quartz-magnetite-schists. > § III, p. ii. 



Hornblende-schists. 

 ^Haematite-schists. J 



1 See A. Holmes & D. A. Wray, Geogr. Journ. vol. xlii (1913) p. 148. 



