419 
opinion that the subjacent schistose rocks have been intruded into 
- or amongst these upper beds, and he states that the grooved and 
fluted surfaces betray the intensity of the forces with which the 
slaty masses were ground against each other. He mentions a quarry 
below the Lion’s Rump at the back of Cape Town, as an example 
of the disturbed position of the schist and overlying sandy rock. He 
suggests that the schists may belong to the Cambrian, and the super- 
jacent beds to the lower portion of the Silurian system. 
The schistose rocks occur also in Robben’s Island ; and on the other 
side of the Lion’s Rump they form a reef of hard rock along the 
shore, occurring at intervals at the bottom of Table Bay, and re-ap- 
pearing in the rounded low range upon the opposite coast. Grooves 
and scratches, as well as ripple-marks, are very prominent on many 
of the slabs. 
2. District from Green Point to Camp’s Bay.—The rocks which 
form the general base of the Lion’s Hill are stated to be best exa- 
mined along the flat shore which skirts it, and where the successive 
formations crop out. ‘The slate rocks gradually attain a nearly ver- 
tical dip as they recede from the Lion’s Rump ; and between their out- 
crop in the sea, where they form the first line of barrier rocks, and 
Green Point, they first change into mica-slate, which soon becomes 
charged with hornblende, then presents a mottled aspect, and gneiss is 
ultimately exposed in contact with granite. At the immediate junc- 
tion of the gneiss with the granite the former is stated to be in some 
places superficially black and vitreous, extremely hard, as vesicular 
as lava, and to be most curiously contorted. Masses of true Lydian 
stone and other metamorphic rocks are stated to be intercalated be- 
tween the ridges of slate. The true beds in the vicinity of the 
gneiss range from S.E. to N.W., but where that rock first appears, 
the strata, as well as the sandstone, dip under the Lion’s Rump at 
an angle of 82° towards the N.E. One line of joints, called by the 
author cleavage-joints, is stated to be inclined 18° to the W.S.W. ; 
and some of the intercalated beds are said to have similar joints 
dipping 23° to the N.W. Directly under the Lion’s Head, where 
the gneiss is in contact with the granite, the beds alter in their 
direction about 5° to the west, the cleavage joints changing also to 
a'range of 30° to the west; and the strata on the shore are in 
utter confusion. At this point commences a series of highly curious 
quartz veins, which intersect the gneiss, passing in some places 
through the joints, as if of posterior origin to the change which pro- 
duced that structure im the rock, and they throw off from each side 
numerous branch veins, often at right angles to the main vein. The 
gneiss is described as overlaid by granite, and the quartz veins to be 
most numerous adjacent to it. Veins of granite are likewise visible 
on the shore, intersecting the gneiss near the junction of the two 
formations; and numerous instances of the entanglement of the 
granite and gneiss were noticed by the author, the fragments of the 
latter, inclosed in the former, being almost invariably coated by 
quartz. It is also stated, that veins of quartz traverse the entangled 
portions exactly in the same manner as the solid mass of gneiss; 
