THE METAMORPHIC ROCKS OF ADELIE LAND.-8TILLWELL. 215 



Fig. 5. Specimen of augite amphibolite found on the moraines at Cape Denison. 

 It contains a large porphyroblast of anorthite (Ab, An,,). These crystals are tinted 

 dark green and are perfectly clear and are a product of the recrystallisation. 







Fig. 6. Specimen of biotite amphibolite, No. 143, collected from an enclosed basic 

 patch in the gneiss at Cape Denison. It contains small nodular crystals of magnetite 

 surrounded by a felspar zone, which passes out into normal amphibolite. Each nodule 

 is looked upon as a metamorphic differentiation centre. 



PLATE X. 



Fig. 1. Metamorphosed gneissic xenolith embedded in amphibolite. The xenoliths 

 are drawn out into an elongated oval form in the direction of the schistosity. Collected 

 in situ in the amphibolite band, No. 629, at Cape Denison. 



Fig. 2. Side view of the specimen in Fig. 1. In section the angular shape of these 

 gneissic xenoliths can be seen, and the schistosity of the rock passes through them 

 irrespective of its outline. 



Fig. 3. This is a more massive specimen than that in Figs. 1 or 2. Note the 

 irregular outline of the metamorphosed gneissic xenoliths. The outline of at least 

 two of these has been rendered indefinite during the recrystallisation. Collected in situ, 

 Cape Denison. 



Fig. 4. The reverse view of the specimen in Fig. 3. The sharp angular outline 

 of a xenolith can be seen near the bottom left hand corner. In this specimen there are 

 xenoliths both with sharp boundaries and without sharp boundaries. This rapid 

 variation renders it unlikely that the xenoliths were partially absorbed by the dyke 

 magma before its primary consolidation. 



Fig. 5. A remarkably angular xenolith consisting of almost pure saussurite. The 

 boundary is perfectly sharp and definite, except for a very small length in the bottom 

 left hand corner. Collected in situ, Cape Denison. 



Fig. 6. A saussurite xenolith in which the re-entrant angle of the primary felspar 

 twin is retained. Collected in situ, Cape Denison. 



PLATE XI. 



Fig. 1. Composite gneiss from Cape Denison in which threads of quartz felspar 

 veins laminate the darker gneiss. The original boundaries are now indefinite. 



Fig. 2. Specimen of granodiorite gneiss with an excessively contorted vein, Cape 

 Denison. 



