PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 75 
imbedded in a most peculiar manner, and occasional nodules and layers of 
plicated folize of chlorite. These are much intermixed with grains of quartz. 
The colour of this chlorite is bright green, mixed with plates of a golden 
yellow; the lustre is high. It is soft and unctuous. The specific gravity of a 
portion, apparently nearly free from quartz, was 2 - 792. 
25 grains yielded— 
Silica, . ; 3 , 2 saat 
Alumina, ; 3 3 20° 424 
Ferric Oxide, . : on 42 
Ferrous Oxide, : ¢ 13:7 993 
Lime, . ; : : *'726 
Magnesia, . ‘ : 23 * 896 
Water, . : : : ded a 
100: 391 
The golden colour may be the result of peroxidation. 
From intrusive (?) Granite. 
8. The gneiss of the Girdleness, in Kincardineshire, is riddled on both sides 
of the point with tortuous intrusive veins of granite. One of these, cut across 
in sinking for the foundations of the new breakwater for the Aberdeen harbour, 
yielded, in small quantities, small crystals of orthoclase, with epidote and small 
scaly chlorite. 
This chlorite is of a dark-green colour and a high lustre; it sheathes the 
crystals of orthoclase, which are pale red in colour. Decomposed crystals of 
pyrite are imbedded both in the chlorite and in the orthoclase. The specific 
gravity of the chlorite is 3 - 038. 
1° 304 grammes yielded— 
Silica, ; : 2 a 
From Alumina, a UUS 
Gu eS 24 +769 
Alumina, . : F . 20° 164 
Ferric Oxide, . : «pe ~ b* 38a 
Ferrous Oxide, : , 2h 308 
Manganous Oxide, . ‘ *613 
Lime, : ; : ‘ “90 
Magnesia, : : . 13° 343 
Watery? : : 22051 
100-59 
Loses 1 ‘453 per cent. of water in the bath. | 
Chlorite occurs extremely rarely in Scotland in granite. One specimen of a 
substance which I take to be it was got at Rubislaw. 
That the goniometer and polariscope can effect the discrimination of well- 
VOL. XXIX. PART I. ul 
