
212 PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 
‘That which is first met with on the west is a pale granite, containing much white 
crystallised quartz,—which is itself unusual,—a nearly colourless felspar, rarely 
tourmaline and graphic garnet, and a mica so colourless and lustrous that this 
locally receives in the district the name of the “sheepy silver vein.” Within a 
few yards of this, there follows a vein with a felspar seldom surpassed in the 
fiery redness of its colour in Scotland; this vein has a rough scorified appear- 
ance. There is in it little quartz, and almost no mica. 
Just at the turn of the promontory two closely-contiguous vems show — 
themselves ; and these interfere somewhat more markedly with the bedding of 
the strata. The felspar of both of these is somewhat similar in appearance; but 
the association of minerals is so very different that the felspar-of both -was 
analysed. 
At no great distance to the east of tkeae the well-known graphic granite— 
correctly pegmatite—vein is to be seen protruding in a line of bosses from the 
turf, and finally thrusting itself in a terminal bluff out of the grass-clad bank. The | 
structure of this vein is so peculiar, and the development of the graphic lettering 
so well marked as to call for a more extended notice than can be here given. 
In the uncovered rocky beach immediately to the east of the graphic vein, 
another, formed like a tesselated pavement, succeeds. The whole mass of this 
vein consists of numberless brick-shaped blocks of felspar, disposed upon their 
narrow sides. These blocks are so arranged as to form sockets for one another, 
from which they can easily be removed ; they are not rude crystals, their frac- 
ture exhibiting quite an unique appearance. A kind of rough twinning of 
crystals, in which there is a parallelism in their axes, shows, by the oscillation 
of the reflected light, like a dovetailing in carpentery, or still liker to the inter- 
lacing of the fingers in clasped hands. Some twenty yards still further west 
the last of the veins is to be seen, running, however, as it skirts the sea, in quite 
a different direction from the others. This vein is of massive felspar, which is 
everywhere studded with fine plumose crystallisations of muscovite. 
Probably at no other ue in Scotland can so many varieties of granitic veins 
be seen. 
From only two of these, however, could felspar pure enough for analysis ° 
be got—namely, the third and fourth,—those protruding from the rocks imme. 
diately at the point. 
The third vein is quite a sata casket, the felspar being plentifully 
studded throughout with finely radiated crystals of black tourmaline,—Iustrous 
muscovite,—occasionally crystallised green apatite,—large crystals of pale red 
garnet with as perfect a graphic structure as that seen in granite,—and either 
epidote, or green tourmaline in minute threads. 
The orthoclase of this veim-is lustrous, of a rich flesh red, and a specific ; 
gravity of 2°561. Contact mineral, mica. Visible impurity, none. 
a.” we tee eee ae ee 
