PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 211 
and a half miles from the foot of the glen, a small vein of granite cuts the strata, 
which consist of a somewhat granular mica schist; this schist a little further 
on, on the other side of the stream, becoming more dense and coherent, has been 
dignified by Maccuttocn by the name of avanturine. - 
The felspar of this vein is of so high a pink colour that, under the impres- 
sion that it could not but be due to manganese, it was analysed. 
Colour, bright pink. §$.G.,2°525, Angle, 90°, Associated minerals, little 
quartz and mica. 
Contact mineral, mica. Visible impurity, none. 
15 grammes gave— 
Riliewie #5 OG) 4 | W986 
From Alumina, f 023 
* 959 = 63° 993 
Alumina, . Ls 17 - 058 
Ferric Oxide, .  . 2-475 
Lime, _ 5 fj "522 
Magnesia, . : ; 066 
Potash, ; ; ‘ 14° 851 
Soda, ; Weake ‘Do 
Water, . : ; SG ail 
100+ 146 
651 of the silica insoluble. 
Possible impurities, quartz and mica. 
There was not a trace of manganese. 
From Dykes in Talcose Slate. 
4, The promontory called Cowhythe Head, which lies about a mile to the 
east of Portsoy, in Banffshire, consists of highly-tilted beds of a talcose and 
micacious schistus, with occasional bands of limestone, serpentine, and “ primi- 
tive greenstone,’—a compound of augite and labradorite. Dykes of granite, 
seyen at least in number, stand among these tilted beds ; they simulate beds 
themselves, as it is only occasionally that they are to be seen disturbing or 
cutting the rocks with which they are in contact. | 
These granitic dykes are very interesting, from the fact that, though following 
close upon one another, they are yet of very different constitution. . 
