EXPLANATION OF THE PLATES 



(Photographs by the Author) 



PLATE I 



Figure 1. — A hand-specimen of Beacon Sandstone ; x § diameter. Note the water- 

 worn quartzose pebble in the lower part of the photograph. 

 Figure 2. — A concretionary nodule weathered out of the Beacon Sandstone, Ferrar 



Glacier ; x § diameter. This has been fractured and hollowed out as described 



in the text. 

 Figure 3. — A saucer-shaped concretionary nodule weathered out of the Beacon 



Sandstone, Ferrar Glacier ; x | diameter. 

 Figure 4. — The pink granite, in situ, at Cape Irizar ; x f diameter. The large 



crystals are pink orthoclase ; the finer material is a mixture of quartz, oligoclase, 



hornblende, and orthoclase. A hornblende -bio tite granite. 

 Figure 5. — The porphyritic grey granite from the Beardmore Glacier ; x § diameter. 



The large individuals are chiefly anorthoclase ; the finer crystallisations include 



quartz, orthoclase, microcline, biotite, and oligoclase. A biotite granite. 

 Figure 6. — The grey granite, in situ, at the foot of the steep ascent to the Larsen 



Glacier ; x £ diameter. This is an even-grained grey biotite granite. 

 Figure 7. — The even-grained grey granite from the Beardmore Glacier; x f diameter. 



The principal minerals are quartz, microcline. anorthoclase, oligoclase, biotite, 



and muscovite. 



PLATE II 



Figure 1. — Orthoclase porphyry from the Stranded Moraines, East Fork. Ferrar 

 Glacier ; x f diameter. The porphyritic crystals are orthoclase : the base 

 contains acid plagioclase, quartz, a little hornblende, and unresolvable devitrified 

 interstitial matter. 



Figure 2. — Grey hornblendic orthoclase porphyry, in situ, at the Kukri Hills, Ferrar 

 Glacier ; x T 9 ^ diameter. 



Figure 3. — Quartz porphyry, in situ, as a dyke -like mass cutting the grey granite 

 twenty miles south-east of Mount Larsen ; x § diameter. Idiomorphic crystals 

 of quartz and orthoclase are seen distributed through a grey felsitic base. 



Figure 4. — Black felspar porphyry occurring as an erratic at a rocky cape about 

 eight miles south of Cape Irizar ; x f diameter. The lower light-coloured portion 

 of the photograph is a grey biotite granite which the porphyry has evidently 

 intruded. 



PLATE III 



Figure 1. — A microphotograph (x 17 diameters) of arkose from the Upper Glacial 

 Depot, Beardmore Glacier. The photograph shows dusty felspars and clear 

 quartzes ; less frequent are darker patches of mica. 



Figure 2. — The same under crossed nicols (x 17 diameters). The albite lamellae 

 in some of the felspar grains are rendered apparent. 



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