78 



AUSTKALASIAN ANTAECTIC LXPEDITION. 



Ti0 2 by the reduction of HC1 solution with tinfoil. A faint trace of the violet colour 

 was obtained in the sample from No. 928, but no trace at all from No. 143. In both 

 cases the mineral is highly magnetic, and the magnetite blebs from No. 143 were found, 

 when suspended by a silk fibre, to possess polarised magnetism. 



Fig. 7. 



Sketch of a nodule in the amphibolite No. 143. A crystal of magnetite is 

 surrounded first by a thin rim of sphene and then by a felspar zone. 

 Crystals of apatite (A) and sphene (S) are distributed through the felspar 

 zone which passes into normal amphibolite by the gradual appearance of 

 hornblende (H) and biotite (B). 



In thin section the rock is found to consist of hornblende and biotite in about equal 

 proportions. The same clear felspar is present in the same proportion as in the normal 

 members of the dyke series. Sphene is again abundant. The crystals are, perhaps, 

 more numerous than in No. 928 ; but the average size is probably less than a quarter 

 of that in No. 928. The magnetite blebs are surrounded by a very thin rim of sphene 

 (fig. 7). Sometimes the blebs tail out a little in the direction of the schistosity. The 

 felspar zone around the magnetite consists of a granulitic aggregate of clear felspar 

 whose grain size is the same as the grain size in the normal part of the rock. The kind 



