64 PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 
It occurred in thin veins in a gabbro, which was composed of apparently a 
dark granular augite or uralite, the crystals of which, of the size of large shot, 
were singly imbedded in a waxy-looking massive labradorite,—‘ Saussurite ” (?) 
The veins were sharply defined, but the labradorite was seen within an 
inch or so of the veins to become greenish in colour and actually to pass by 
insensible gradation into the mineral described. 
The colour of this substance in the veins was pale sap-green : it was trans- 
lucent, tough, and like slate-pencil, and had a specific gravity of 2:59. There 
were no associated minerals. 
1-264 grammes yielded— 
Silica, ‘ . *431 
From Alumina, . °008 
* 439 = 34° 731 
Alumina, , ‘ z , 12-444 
Ferrous Oxide, . é 2 wos 
Manganous Oxide, . e erledi 
Lime, : ‘ : Cel Soe 
Magnesia, : , . 34°098 
Waters; 5 : » W3ast 
99 - 822 
Insoluble silica, 6 * 884 per cent. The specimen analysed was perfectly pure. 
Since the above analysis was made, my attention has been particularly 
directed to pyrosclerite by Professor Kine of Galway, with a view to the cor- 
relation of the gneissic limestones of the west of Scotland with those of Conne- 
marra in Ireland. 
The Beauty Hill mineral differs from a specimen of pyrosclerite sent to me 
by Professor Kina as from Elba, in the single respect of being somewhat 
harder, perhaps also in being a little paler in colour. But it is a question if 
the Elba mineral is truly pyrosclerite. 
Dana makes pyrosclerite a micaceous mineral, with. eminent cleavages ; 
pseudophite he refers to as compact-massive, and without cleavages ; in other 
physical characters, as well as in chemical composition, they are almost 
identical; and if, as is held, pyrosclerite occurs in a colloidal state, it is not 
easy to see how any line can be drawn between the two. 
As regards the present mineral, considered in the light of the slight differ- 
ences which do exist between them in their typical forms, it more agrees with 
pyrosclerite in hardness,—with pseudophite in gravity and in structure,—while 
its being apparently an alteration product of a /élspar, is a feature which has 
as yet been assigned to neither. As certain of the “colloidal pyrosclerites ” 
sent me by Professor Kine, both from St Phillipe in the Vosges, and from 
Ireland, very much resemble pseudomorphs (set down as serpentine after 
