1915- ^O- 4- REPORT ON ROCK-SPECIMENS. 27 



2. Loii'er Cambrian; slightly altered limestones with fossils. 



3. Post-Catnbna)! and Pre-Condicana ; intrusive masses of granites of 

 various types, 



4. Gofidicana ; "Beacon Sandstone""* with fossil plants and among them 

 g/osso/)/ens indica ~'. 



5. C retaceoKS ? dikes or sills of diabase or dolerite intruding the Beacon- 

 sandstone and the granite. 



6. Post-Pliocctie : volcanic rocks (lavas and tufts). 



Among the formations cited only the pre-Cambrian rock-complex of 

 gneisses and cr3"stalline schists and the post-Cambrian intrusive granites 

 show relationship with the rocks collected on Roald Amundsen's Expedition. 



Prc-Cambrian. The rocks met with in the basal rock-complex of 

 pre-Cambrian age are according to Ferrar"*, Priestley and David ^. gneisses, 

 coarse pegmatite, mica-schists, amphibolite-schist, granulites and other crj'stal- 

 line schists. According to Prior-* "'the gneisses are metamorphosed granites 

 (orthogneiss) and are often characterised by prominent augenstructure and 

 by cataclastic effects". This complex of highly metamorphic rocks seems 

 to form the base of the other rock-complexes in South \'ictoria Land and 

 has already by G. T. Prior 1902 "^ been cited as the probable basal rock- 

 complex. Priestley and David -^ express the opinion that "the Cambrian 

 rocks were deposited on the surface of a very old peneplain of pre- 

 Cambrian gneisses and schists". Limestone is not found in this complex. 



The pre-Cambrian complex of gneisses and crystalline schists was 

 found in Adelie Land (140 — 145° L. E. Gr.) by Mawson's Antarctic Expedition 



Post-Cavibnan and pre-Gomhoana intnisive graniics. Priestley and 

 David '' describe large intrusive masses of granite of various types, ranging 

 from somewhat basic to acidic. In the natural sections the granitic deep-seated 

 rocks occur above the gneisses. Prior ■* describes "masses of red and gray 

 granite occuring above the gneisses and occasionally passing into more 

 basic diorites or hornblende-gabbros" ; as dike-rocks intersecting the gneiss 

 and the granite are mentioned: camptonites, kersantites, quartz-porphyries 

 and banakite. The determination of the age of the intrusive granites is 

 based upon the observed contactmetamorphic alterations in the associated 

 graphitic calc-schists, limestone with chondrodite and marble, assumed to 

 represent altered Cambrian rocks. Large masses of quartzite are also 

 obser\'ed as inclosures in the granite as well as amphibolitic rocks. The 

 granites are certainly younger than the pre-Cambrian complex of gneiss 

 and crystalline schists, and according to Priestley and David also younger 



