THE MINERALOGY OF SCOTLAND. 465 
< F ; : 
[ido not remember ever having examined a mineral which was so absolutely 
free from the minutest trace of iron as was this psilomelane. 
3. From the mines which have been opened on the west side of the road 
passing from Cock Bridge to the Laoch mines. These mines lie near the 
north-east foot of Alsait Hill. 
Colour, clove brown; lustre, vitreous; fracture, conchoidal; structure, 
massive and pilch like ; powder, orange-brown. 
On 1° gramme— 
=. G. 3°65. 
Ferric Oxide, 52° 094 
Alumina, 8° 215 
Ferrous Oxide, Dn oon 
Manganous Oxide, : ; "o 
Lime, . ‘ : ' ; ; “Gide 
Magnesia, . F : : ; ; °5 
Silica, , ; : : ’ a 
Water, ‘ ; 2 : : , 14° 569 
99772 
Loses in bath, 1° 989 per cent. of water. 
I do not know what to make of this. While gathering it, I conjectured 
from its appearance that it was the rare mineral “mnite; but now, after 
analysis, it gives promise of being a new mineral. I have seen a substance 
identical in appearance, except that it was still more lustrous, at Leadhills. 
This last, however, may prove to be limnite. I have not yet obtained a 
sufficiency of the Leadhills mineral for analysis. 
4. Occurs on the south side of Garron Point, north of Stonehaven, in a very 
peculiar green argillaceous rock, ordinarily called chlorite slate. It, however, 
much more resembles a glauconitic clay-slate, with a fissile structure. 
The colour of the iron ore is ochre-brown ; its structure is laminated or 
bedded, the layers being shown by thin rifts of a darker colour. It was called 
magnetite by NIcot. 
It is hard, more like a laminated clay iron ore, than a simple mineral. It 
was once wrought by the Carron Iron Company. 
