4t PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 
about a year before the writer obtained the specimens; this rock cutting was 
about 20 feet in depth, and it was nearly at this greatest depth that the 
specimens: were gathered. The locality is near the farm of Badnagauch, on 
the Deskery, in Aberdeenshire. The rock is the syenite of Morven, here 
much decomposed—heing almost gravelly. Through this rock numerous anasti- 
mosing exfiltration veins occur ; there is also an intrusive porphyry vein. The 
exfiltration veins had not suffered nearly so great.an amount of change as the 
rock mass ; indeed, except. as regards the mica, there was little or no change 
in them. They contained large crystals of dark-green hornblende ; large and 
finely-shaped crystals of labradorite, a few, apparently, of muscovite ; granules, 
the size of peas, of menaccanite ; folize of the mineral in question of about an 
inch in size; sphene and Allanite rarely. None of these minerals, with perhaps 
the exceptionof the mica, showed any appearance of change. It was in dark- 
brown, rather dull crystals, which in parts were somewhat softened and 
bronzy ; the amount of change did not, however, appear to be great. The 
crystalline foliz were somewhat loose. The specific gravity, taken on the 
mineral in its ordinary state, was 2°63 to 2'645; after being boiled to expel 
air it was 2° 845. 
1° 302 grammes yielded— 
Silica, . : : , “42 
From Alumina, . : 10% 
‘43 = 30°026 
Alumina, . : : » Jocton 
Ferric Oxide, . : © 26°07: 
Ferrous Oxide, . 2:°009 
Manganous Oxide, . : °153 
Lime, " : é 1°634 
Magnesia, . 4°831 
Potash, , 4°02 
Soda, : ; oe a SaNGi, 
Water, ; : ' . 13882 
99°95 
Was apparently pure. It contained no fluorine. The portions which appeared 
to have suffered some change were, as far as possible, cut away. 
It lost in bath 5-731 of this water; the greater amount of this was lost 
in half an hour—the whole in half a day. 
This composition is unquestionably nearer to that of lepidomelane than to 
Biotite ; indeed, it is like a hydrated lepidomelane. The writer is disposed, 
however, to regard this as a fortuitous resemblance. It is difficult to believe 
the mineral to be merely a hydrated mica; these are not prone to exces- 
sive alteration, and the duration of the exposure could hardly have been suffi- 
