220 GENERAL GEOLOGY 



been deposited on the beds by glacial action. Many of these kenyte boulders were 

 burnt a brick red and coloured with sulphur, as if they had been part of the lining 

 of the vent by which the basalt was poured out, and had been torn off by the 

 explosive action of the steam and gases accompanying the eruption. 



There are, therefore, two pieces of evidence which combine to show that the 

 basalts of Cape Barne were forced through a series of pipes drilled through the 

 older beds of kenyte. First, there is the occurrence of the kenyte boulders weathered 

 out from the basaltic agglomerates, and secondly, the occurrence of baked and 

 sulphur-covered fragments of kenyte in the tuffs of the sugarloaf hill. 



There is also little doubt that the kenyte of the newest of the Erebus craters is 

 more recent than the basalt of Cape Barne, so it seems probable that at or about 

 the time that the volcano at Cape Barne was erupting basalt the main crater of 

 Erebus was erupting kenyte, and therefore that the lava of Cape Barne is the 

 product of a subsidiary reservoir which was, at any rate at the time of eruption, cut 

 off in some way from the main Erebus reservoir. 



The evidence of glacial action all points to the Cape Barne lavas being either 

 preglacial or interglacial. 



The basaltic rocks of Cape Barne are reported by Dr. H. I. Jensen to contain an 

 extraordinarily high percentage of magnetite (in one or two cases as much as 50 per 

 cent.), and that the magnetite, contrary to its usual habit, is amongst the latest 

 products of crystallisation. 



EREBUS 



PARASITIC CONES AT LOW LEVELS 



Mount Cis. On October 8th the nearest of a number of small conical hills 

 about a mile back from the coast, and near the 700 feet contour line, was examined, 

 and proved to be the remains of a small parasitic cone of a very peculiar type of 

 rock. The only part of the cone now remaining is a plug of lava, which evidently 

 formed the neck of the volcano. It is of course quite possible that there never were 

 any liquid extrusions, and that this plug was solidified beneath the surface. On the 

 southern and western side the hill is flanked by a scree of angular debris, all of it 

 clearly derived from the hill itself. The scree probably is continuous right round 

 the hni, but on the other side it is hidden by a snow-drift. 



The hni looks decidedly top-heavy, its diameter being less a few feet down 

 than at the top, for it is strongly undercut on its southern side. It was this 

 appearance that caused its close examination, for the only way for accounting for 

 this shape was by presuming that it was composed of rock in situ, and would not 

 prove to be an esker, composed of miscellaneous rubble. The rock is highly jointed, 

 and undoubtedly in situ. Its small extent, and the fact that few fragments 

 would be identifiable, has probably prevented its recognition amongst the moraine 



