264 SUPERFICIAL DEPOSITS 



lateral moraines eastwards, and eventually sweeping nearly all this moraine with 

 foreign erratics into the sea. 



A curious feature in the moraines of Cape Royds are the curious conical 

 moimds on or in the ice of Blue Lake. These have already been referred to in 

 Chapter V. Their general appearance is shown on Fig. 1 of Plate LXXXV. 



They occur at a short distance from the eastern shore of Blue Lake. We were 

 not able to ascertain whether their foundation was lake ice or rock. An interesting 

 feature was observed in the distribution of erratics near the top of Crater Hill, near 

 Hut Point. 



Crater Hill rises about 1000 feet above sea-level, and its crater is about 200 

 feet deep (Ferrar, op. cit., p. 12). Small erratics were discovered by us within this 

 crater. 



The occurrence of these small erratics at the top of Crater Hill makes it very 

 surprising that the hill should have retained such a perfect form, for its rim is knife- 

 edged. We were for a long time inclined to think that Crater Hill was post-glacial 

 on account of this sharpness of its rim, but in the light of the evidence at present 

 available this seems impossible, and we can only surmise that the glaciation to 

 which it was subjected was very slight. 



It is curious that all the erratics met with at Hut Point were uniformly small. 

 No single specimen contained more than three-quarters of a cubic inch of rock. This 

 is remarkable when these are compared with those comprising the moraines at Cape 

 Royds, where blocks of every size, from half a cubic inch to many cubic feet in mass, 

 are to be seen. It seems also that off Cape Armytage the ship traversed a moraine 

 just deep enough to allow of her passage and some hundreds of yards broad, and 

 composed of material more comparable with that comprising the morames at 

 Cape Royds than those at Hut Point. Possibly the erratics at Cape Royds may 

 have been transported thither by some glacier from the Western Mountains like the 

 Koettlitz Glacier, or some glacier farther south, whose moraine missed Hut Point, 

 but reached Caj^e Royds. 



Amongst the specimens picked up were several of quartzlte, and a sandstone not 

 unlike the Beacon Sandstone of the west, whilst many kinds of felspar-porphyry and 

 granite were common, while other specimens, more indeterminate in hand specimens, 

 were probably diorite and dolerite. 



Beyond these small fragments of foreign rocks the moraines generally consisted 

 of large and small, often sub-angular, fragments of basalt, the olivine basalt with 

 included nodules being quite common, and also both black and red non-porphyritic 

 basalt, and a red glassy scoriaceous basalt containing numerous small phenocrysts of 

 augite. It was curious that trachyte fragments were not very common away from 

 the neighbourhood of Observation Hill, in which that rock occurs in situ. 



Reference has already been made (Chapter V.) to the occurrence of great 

 moraines on the western side of the Beardmore Glacier, together with the immense 



