3l8 POLAR PROBLEMS 



Cambrian 



Limestone fragments in breccia of Beardmore Glacier with Archaeocyathus, 

 Protopharetra, and Epiphyton. 



Devonian 



Shales (? estuarine) of Granite Harbour containing fish plates and probably 

 forming the base of the Beacon sandstone. 



Pernio- Carboniferous to Rhetic 



Beacon sandstone (5000 feet) with wood fragments, coal seams, Glossopteris 

 indica, Rhexoxylon priestleyi, Vertebraria, etc. 



? Upper Jurassic or Cretaceous 



Quartz dolerites in sills (and dikes), intruding younger granites, and Beacon 

 sandstone. Thickness up to 2000 feet. 



Late Tertiary 



Palagonite tuffs, limburgites, kenytes, trachytes, phonolites, etc., Mt. Erebus, 

 Mt. Discovery, Mt. Melbourne, Possession Island, Cape Adare, etc. 



Recent 



Low-level and high-level moraines, raised beaches, kenyte lavas of Erebus. 



The structure of the horst region of South Victoria Land is revealed 

 in a basement of the pre-Cambrian complex, surmounted by a great 

 thickness of horizontal or slightly inclined Beacon sandstones, in- 

 truded by thick sills of quartz dolerite. 



Uncertainty about the chronological position of the Robertson 

 Bay slate-graywacke series and the younger granites still exists. 

 The former series are shown by Priestley to be folded along northeast- 

 southwest axes, with more intense folding towards the east. The 

 younger granites have been seen only in relation to the older pre- 

 Cambrian rocks and, for all evidence to the contrary, may themselves 

 be of pre-Cambrian age. Cambrian rocks are known only through the 

 evidence of Archaeocyathus limestone forming portion of a lime- 

 stone breccia found as erratics on Beardmore Glacier. The location 

 of the source of the Cambrian limestone, its structural character, and 

 its relations to the granites of the Beardmore Glacier mountains will 

 shed new and important light on the hiatus now existing in the stratig- 

 raphy and tectonics of Lower Paleozoic time in this quarter. 



The fundamental rocks of Adelie Land and Queen Mary Land 

 are metamorphic sediments and igneous gneisses found both in situ 

 on the coastal nunataks and islets and profusely in moraines. The 

 wide extent of the Beacon sandstone and of the quartz dolerite sills 

 which intrude it is clearly indicated by their discovery in King George 

 V Land. In the vicinity of Horn Bluff (150° E.) a sweep of coast line 

 bounded by rocky cliffs looo feet high is built up of red sandstones 

 containing coal and carbonaceous shales. These outcrop at a height 

 of several hundred feet and are capped by an immense thickness of 

 dolerite sills. In the moraines of Adelie Land (at Mawson's winter 



