TRANSACTIONS OF SECTION C. 397 
The rocks that compose the range are conveniently separated into four distinct 
groups—namely, gneisses, granites, sandstones, and dolerites. The sandstone, to 
which it is proposed to give the name Beacon Sandstone Formation, provides a con- 
venient stratigraphical datum line, with reference to which the other phenomena 
may be considered. 
(i.) The gneisstc rocks occur at sea-leyel and below a sequence of rocks which 
is at least 12,000 feet thick, and may be safely regarded as forming the ancient 
platform on which the central part of South Victoria Land is built. The foot-hills 
of the Royal Society Range and the lower portions of the Cathedral Rocks are 
composed of this class of rock. 
(ii.) The granites have been encountered at the north end of the Royal Society 
Range, where they rest upon gneisses, and dykes of granite pierce the gneissic 
series. At Granite Harbour this type of rock is found as a huge boss, and is 
robably covered by a sheet of dolerite. Where the Ferrar Glacier bifurcates, a 
Junction of dolerite and granite proves that there are two distinct developments of 
granite, one older and one younger than a certain sheet of dolerite. 
(iii.) The Beacon Sandstone Formation is met with at a height of 4,000 feet above 
sea-level, and about 40 miles from the sea. It appears to be nearly 3,000 feet thick, 
and near the top indeterminable fossil plants were found. The bedding is practi- 
cally horizontal, and the rock is remarkably uniform in texture. The surface upon 
which it rests has not yet been discovered. 
(iv.) The dolerite sheets produce the plateau-features characteristic of that rock, 
and cap the sandstone over a very large area. Dykes, sills, and pipes of the dolerito 
occur in the sandstone, and prove the former to be intrusive. The original dolerite 
plateaux have bee dissected by water action, apparently prior to the faulting 
which has dislocated the Beacon Sandstone. 
IV. The Ice.---Sea ice, produced by the freezing of the sea during the winter, is 
on an average 8} feet thick, but during the summer the sea-water melts the lower 
surface of the ice. Shore-ice, a fringe of glacier ice attached to the land, shows 
the conservative action of ice in this latitude. Inland ice, local ice-caps, piedmonts, 
aud other types of glaciers may be recognised in South Victoria Land. The term 
‘ floating-piedmont’ has been suggested as descriptive of the Great Ice Barrier, or 
Ice Sheet, of Ross, and there are at least three examples in our area. 
The moraines high on the slopes of Mount Erebus, and other moraines stranded 
at various spots, are considered in their relation to the past and present distribu- 
tion of the ice, and the conclusion arrived at is that the glaciation is approaching 
a minimum, 
5. Baviaan’s Kloof - & Contribution to the Theory of Mountain Folds. 
By Ernest H, L. Scuwarz, A.2.C.8. 
Baviaan’s Kloof is a narrow valley lying between mountains formed during the 
Triassic period. The subsequent geological history may be summarised thus :— 
(a) First base level. Deposition of the Enon Conglomerate, derived from the 
disintegration of the newly formed mountains, on a plain or flat double-bevel 
eroded between the two mountain chains. 
(6) Period of cross-folding. ‘The area was traversed by two sets of folds in 
directions W.N.W.-E.S.E. and S.W.-N.E., which let down portions of the sur- 
face in deep pits, bounded by circular faults and sharp folds. 
(c) Second base level. The Enon Conglomerate was removed, except that in 
the fold-basins, and the surface of the valley again reduced to a double bevel of 
erosion, 
(Z) Rising of the land. Deep erosion of the river channels; immense gorges 
cut in the floor of the plain and most of the loose Enon Conglomerate remaining 
in the fold-basins removed. 
_ Cross-folding is the interpretation of the two sets of mountain folds, and the 
sinking of areas in the meshes between them is contrary to what would happen if 
