12 R. H. CAMBAGE. 



those in the Argentine and Southern Brazil in Lower or 

 Middle Gondwana time, these would suggest that conditions 

 were not favorable for the formation of pure seams of coal 

 of any great thickness so far south during those epochs. 

 Nevertheless the fact must not be lost sight of that it is 

 quite possible that after all the Beacon Sandstone forma- 

 tion may be of Upper Gondwana (Jurassic) or even of 

 Cretaceous age. 



Rich collections of minerals, far exceeding in variety 

 and development anything which previously has been 

 obtained from the Antarctic Continent, have been brought 

 back by Mr. S. P. Stilwell, m.So., the geologist in charge at 

 Dr. Mawson's head-quarters. Altogether about a ton of 

 specimens has been secured. These comprise (in addition 

 to minerals such as garnet, scapolite, tourmaline, beryl, 

 apatite and magetite, etc.) metallic minerals also, of com- 

 mercial value, such as for example molybdenite, antimonite 

 and carbonates of copper. 



In regard to glacial conditions at Dr. Mawson's main 

 base it would seem as though the ice sheet has been 

 retreating rapidly there in recent times, inasmuch as low 

 hills of gneiss and schist at the head-quarters at Common- 

 wealth Bay show a beautiful fresh glaciated surface, the 

 striae being in a perfect state of preservation. When one 

 considers that frost-weathering due to rapid changes of 

 temperature between night and day quickly destroys by 

 splintering any freshly exposed rock surface, it is evident 

 that these glaciated rock surfaces have been very recently 

 uncovered through a retreat southwards of the great ice 

 sheet. This retreat is taking place in spite of the fact 

 that this portion of the Antarctic ice-cap is more plentifully 

 nourished with snow from all its areas further south to the 

 west of Mount Erebus etc. Here, one must note that it 

 does not necessarily follow, as Mawson has shown, that 



