THE DOLERITES OF KING GEORGE LAND AND ADEL1E LAND- BROWNE. 253 



the rock No. 732A, the results of which are given in column J l>do\v, the 

 analyses of three other quartz-dolerites from Antarctica and one from Tasmania being 

 added for comparison : 



I. Horn Bluff Dolerite No. 732A; 



TI and III. Erratics from Cape Royds, South Victoria Land. Geology (Vol. II), 

 British Antarctic Expedition, 1907-9, p. 157. 



IV. Erratic from Knob Head Moraine, South Victoria Land. National Antarctic 

 Expedition, 1901-4, Natural History, Vol. I., Geology, p. 137. 



V. Enstatite-augite-bearing Diabase from Launceston, Tasmania. Osann, Central, fur 

 Min. 1907, pp. 701-711. 



An inspection of these analyses shows that of all the South Victoria Land rocks 

 N<>. Ill is most closely related to the Horn Bluff rock, and that there is a distinct 

 chemical resemblance between them, but that a very much closer and very remarkable 

 agreement exists between the Horn Bluff dolerite and the Tasmanian diabase. The only 

 points of apparent difference are in the higher Fe 2 3 and H 8 of the Tasmanian rock, 

 which are possibly to be attributed to surface alteration. The norms of the three rocks 

 in question emphasise the closeness of the relationships: 



