AT THE CAPE OF GOOD HOPE. 
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nite of less distinct crystalline characters; in other words, a granite 
of smaller grain. In this view the small-grained granite at Green 
Point might be considered in the condition of a vein from the large- 
grained. The sajne explanation will go far to explain the different 
charaters of the veins in Table Mountain. Those of the greatest 
width, in some places entirely, and in all much resemble the rock 
which gives them off. Those of a smaller or of a gradually dimi- 
nishing width, are of a large grain at their origin, but become of a 
smaller grain as they recede from it ; that is, they are of a less definite 
character where, according to the theory of the igneous origin of 
granite, they cooled with the greatest quickness. 
But however well the condition of these rocks may be explained 
by the agency of fire, the operation of water is no less plainly 
pointed out by the horizontal strata of sandstone, and the appear- 
ances attending its junction with the granite. Yet whilst the general 
fact of the aqueous deposit of the great sandstone strata forming the 
summits of the Cape mountains, and their undisturbed rest since, 
cannot escape observation, it is a task of some difficulty to unravel 
all the phenomena attending their junction with the granite. Having 
endeavoured to point out their general order, I shall here venture 
to suggest those consequences to which they seem to lead. 
The appearance which, from its universality, especially presses upon 
the notice, is the decomposed state of the constituents of granite, 
whether forming the bed immediately resting upon granite, or a part 
of the porphyritic conglomerate, resulting from their mixture with 
red sandstone. Three principal conclusions may, I think, be drawn 
respecting it. First, that the decomposition has not arisen from 
any late action of the elements; secondly, that it occurred before the 
deposition of the great sandstone formation ; and, thirdly, that it 
happened when the surface of the granite, in a greater or less 
degree, formed the surface of the land. 
That “ the decomposition has not arisen from any late action of 
the elements,” is proved by the great compactness and toughness 
of the rocks in which it occurs, and by the fact that granite in their 
