466 PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 
what laminated variety of apparently the same mineral, and labradorite, in a 
crypto-crystalline form. The larger masses of the mineral in question occurred 
either in imbedded crystals, in coarse-grained patches of the rock, or in exfil- 
tration veins. In the latter they were associated 
NS DONG with Paulite, menaccanite, labradorite, pyrite, and 
Biotite. (%) 
The rock, as a whole, may be regarded as in- 
termediate between diorite and hyperite. 
a This augite is occasionally in rough imbedded 
crystals of the form shown. More generally it 
presents flat cleavable surfaces like the lower 
figure. The colour is brownish or yellowish brown; 
it is semi-transparent. 
The cleavage is flat and decided, parallel to a, of 
which the lustre is vitreous. There is no face of 
bronzy or metallic lustre. There is a slight ap- 
pearance of decomposition ; and in specimens, evidently of the same mineral, 
got from the shore at Cowhythe, the colour is greenish, with, on weathering, a 
pinchbeck lustre ; and, here, polished faces seem to show an absolute passage 
of the unaltered greenish mineral into true unweathered violaceous Paulite. 
AUGITE 
& 

The specific gravity is 3°28. 
1:3 grammes yielded— 
Silica, ‘ , . soul ans 
Alumina, . ‘ ob AAG 
Ferric Oxide, . ; » pore 
Ferrous Oxide, ‘ oO fOe 
Manganous Oxide, . 307 
Lime, ; : ¢ Py ates 
Magnesia, : : + "HG" 615 
Potash, . : : : °188 
Soda, ; s : : °899 
Water, : : 3 : OTe 
100° 435 
This, apparently, is the mineral which forms the greater part of the bulk of 
the beds of diorite—if they are to be so named—which occur in the bay of 
Durn near Portsoy. The rock there would appear to contain this mineral 
(almost entirely replacing hornblende), Paulite in varying amount, labradorite, 
andesine rarely—either in small tortuous veins, or in stellate crystallisations— 
Biotite, menaccanite, pyrite, and pyrrhotine. There are at least five alterna- 
tions of this rock with serpentine in the space of some 50 yards, and some of | 

