PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 21 
1:3 grammes yielded— * 
Silica, : f ae: 
From Alumina, . °01 
“pal = 40°06 
Alumina, : : . 12°408 
Ferric Oxide, ‘ f . 138°474 
Ferrous Oxide, ‘ . 2°668 
Manganous Oxide, : «* 7615 
Lime, : 4 , . 11076 
Magnesia, ; é . 14°661 
Potash, ' ; ; On 
Soda, ; ; : 5 wai Los 
Water, : p : . 99293 
99 994 
Loss in bath none; insoluble silica, 2° 879 per cent. The “ glass ” is of the 
same pitchy blackness as that from the last locality. 
Lepidomelane. 
S.G Si ‘Alp. | Fey. | Fe. | Mn Ca, | Mg. | Ke. | Nag | He Total. 
Achadhaphriz, . , 2°971 || 40°38 | 12°11 | 14°58) 3°03) 3°15) 1:03] 13° 713) 1°8 3°57 || 99°72 
Tongue, : : : 2°965 || 40°08 | 12°41 | 13°47 | 2°67 62) 1:08] 14°66} 7°57) 2°15) 5°29]| 99°99 
HAUGHTONITE. 
From Dykes in Hornblendic G'neiss. 
Lepidomelane—the ordinary black mica of the granites of Ireland—has 
been shown to be extremely rare in Scotland. There is another black, 
indeed much blacker mica, which is extremely common; this, however, 
is a perfectly different, in fact an unrecognised, if not an altogether new 
mineral. 
I give the occurrence, description, and analyses first, and consider the 
question of specific-individuality later. 
Two huge vertical granitic dykes cut the north-eastern foot of the great 
hill of Roneval in Harris ; the most southerly of these runs from Loch Finsbay 
through the hill, striking towards the west shore; the other is seen half-way 
between this and Scuir Ruidh. 
VOL. XXIX. PART I. F 
