260 AUSTRALASIAN ANTARCTIC EXPEDITION. 



riot, 

 4. Gabbro Schists and Gneisses 268 



These differ from the other amphibolites in possessing an apparent coarse grain-size due to their 

 derivation from coarsely-crystalline gabbros. 

 No. 915, a garnet-biotite-amphibolite. 



No. 990, similar to No. 915 in which brown biotite is replaced by green chlorite. 

 No. 339, garnet-plagioolase-gabbro-gneisg. 



No. 593, the gabbro structure is so well pronounced that the rock is sirailiar to a hornblende -gabbro 

 No. 367, with augen structure and the augen consist of aggregates of calcic andesine. 

 No. 969, with augen of saussurite. 

 No. 317, saussurite-gabbro-gneiss. 



No. 728, gaussurite-gabbro-gneiss with traces of the outlines of the original felspar. 

 No. 861, saussurite-gabbro-gneiss with well-preserved form of original felspar. 

 No. 515, saussurite-gabhro-gneiss with branching veins of lawsonitc and chloritisation of the hornblende. 



III. Group V. Magnesium Silicate Gneisses 271 



1. Kata Division 271 



No. 587, pyroxene rock. 



No. 963, hornblende-pyroxene rock. 



2. Meso Division 271 



No. 594, garnet-hornblende-schist. 



No. 513, anthophyllite-schist, with abundant green hornblende and areas of talc. 



No. 516, anthophyllite-schist with green hornblende and without areas of talc. 



No. 109, anthophyllite-schist with plagioclase and without green hornblende. 



No. 548, hornblende-fels, consisting wholly of hornblende. 



No. 950, biotite-hornblende-schist. 



No. 941, hornblende-fels, with granulitic hornblende developed from lar^c platy hornblende. 



No. 209, hornblende-schist with areas of talc. 



No. 246, aotinolite-schist. 



3. Epi Division 274 



No. 229, chlorite-hornblende-schist. 



No. 888, hornblende-schist with large crystals of chlorite. 



No. 229, ohlorite-hornblende-schist. 



No. 916, epidote-chlorite-schist. 



No. 931, epidote-hornblende-schist. 



IV. Group III. Plagioclase Gneisses 275 



Tliese rocks are more acid than the amphibolites and contain less hornblende or its equivalent. 



1. Meso Division 275 



Nos. Ifi9, 170, hornblende-plagioclase-gneiss with schliercn of amphibolite and pyroxene. 

 No. 378, hornblende-felspar-gneiss, containing microcline as well as plagioclaso. 

 No. 259, hornblende-plagioclase-gneiss, with subordinate biotite. 

 No. 240, Biotite-plagioclase-gneiss, with subordinate hornblende. 



No. 956, Biotite-hornblende-felspar-gneiss. The hornblende resembles actionolite in form nd colour, 

 and biotite is more reddish than usual. 



No. 51, hornblende-quartz-plagioclase-schist, with hornblende porphyroblasts embedded in a fine grami- 

 litic ground mass of quartz and felspar. 



No. 924, hornblende-plagioclase-schist, resembles a porphyroide, but the base is a mass of densely-packed 

 needles of hornblende. 



