222 GENERAL GEOLOGY 



OTHER PARASITIC CONES 



A few hundred yards up the slopes of Erebus, due east from Tuft' Cone, were 

 a bunch of three or four conical hills, with one or two more scattered within a short 

 radius. One or two of these proved to be eskers, but the majority were plugs of 

 massive kenyte which had either occupied the necks of parasitic cones which have 

 since been denuded, or had been intruded near the surface and since weathered out. 



On February 13th, on the way back fi'om Cape Barne with a load of mlrabilite, 

 we stumbled on the remains of another parasitic cone, just above the terrace at the 

 east of Backdoor Bay. The remains at present consist of a much denuded sugar- 

 loaf, only a few feet high, and formed of a very fine-grained and finely laminated 

 brown tuft', containing large blocks of a pumice so much altered, and so very friable, 

 that blocks 18 inches thick could be crushed to powder by the pressure of the hand. 



HUT POINT 



Lavas. The peninsula, of which Cape Ai'mitage is the extremity, and on which 

 Hut Point is situated, is built up of a series of lavas and tuft's which are the 

 product of subsidiary volcanoes situated on what may be termed the Erebus frac- 

 ture zone. Castle Rock, a plug of palagonite tuft", and the highest point on the 

 peninsula (1300 feet), is the denuded remains of such a volcano. Others are the 

 Sulphm* Cones (basalt). Crater Hill (scoriaceous red basalt glass). Harbour Heights 

 (olivine basalts), and Observation Hill (trachyte with a horizontally bedded tongue 

 of basalt on its south-west side). This district has been described in fair detail by 

 Ferrar in the Geological Memoir- of the National Antarctic Expedition, 1901-4. 

 During our short stays at the Hut a few observations were made. 



Small foreign erratics were very numerous, and were found at the top of Crater 

 Hill, a few being picked up inside the crater itself, and at a small scoria cone just 

 a short distance north-east of Crater Hill. They M^ere also found in great numbers 

 on Cape Armitage, and to within 100 feet of the toji of Observation Hill. There 

 was a quite obvious reason why they were not found any higher than this, for the 

 leeward slopes of the hill were covered with snow, and the top of the hill had been 

 carved into a sharp ridge which was almost unencumbered with small debris, and 

 which had been weathered by the wind into a series of fantastic shapes. These 

 small foreign erratics were also very common in that portion of the Gap moraines 

 which we saw fi-'ee from snow. 



A very interesting question is suggested by the occm-rence of these small erratics 

 at the top of Crater Hill. The edge of Crater Hill is remarkably sharp, and it is 

 inconceivable to believe that the summit of the hill has ever been heavily glaciated. 

 The sharpness of the rim of the crater and the fi-esh appearance of the scoriaceous 

 lava is suggestive of the crater being post-glacial in age, and yet how are we to 



