410 Mr. Macgillivray’s Account of the Outer Hebrides. 
iron ore, garnet, and other minerals. and in one of them I found 
crystals of beryl. . 
The simple minerals which I have observed in these islands are 
the following : 
Felspar, white, flesh-coloured, deep red, gray. 
Adularia, forming a constituent of granite veins. 
Quartz, white, bluish, rose-red, greenish, brown. 
Mica, silvery, pale green, dark green, brown of numerous tints, 
black. 
Chlorite, foliated in granite and gneiss, slates. 
Potstone ; this is probably chlorite in minute particles. 
Asbestus, stelliform, ligneous, &c. 
Amianthus, gray, and not so fine as that found in Shetland ; alse 
in minute greenish veins in potstone and serpentine. 
Talc, common green and blackish. 
Anthophyllite, greenish gray. 
Hornblende, abundant in the gneiss, and forming beds. 
Schorl, in granite veins, in Lewis and Harris. 
Actynolite, plentiful in Harris. 
Bronzite, at Marig. 
Sahlite, Coccolite, Diallage, in limestone at Rodell. 
Carbonate of lime, forming limestone and stalactites. 
Iron pyrites, interspersed in the gneiss. 
Copper pyrites, not common. 
Magnetic pyrites, in chlorite slate in Harris. 
Zircon, in potstone. 
Calcedony, in small specks in trap veins. 
Zeolite, in the trap veins. 
Garnet, very abundant, and in numberless varieties ; regularly 
crystallized in the granite veins, and often forming a principal con- 
stituent of the gneiss. 3 
Titanitic iron ore, in nodules in the granite veins, not uncommon. 
Beryls, crystallized, in the granite vein of Bencapval. 
To these may be added porcelain earth, clay, and bog iron ore. 
In the abeve remarks I have merely given a very general view. 
of the geology of these islands. The details, which are highly in- 
teresting; I intend to present in a separate form, when I have com- 
pleted the observations necessary for their full apprehension. It is 
strange that these islands should have been so little visited, or that 
gneiss, the most important of the primitive formations, should to 
the only geologist who has visited these countries, Dr. MacCul- 
ioch, have seemed so uninteresting, that he always appears anxious 
to get rid of it. ‘The connection of the unstratified granitic masses 
with the gneiss, the general direction of the latter, the phenomena 
exhibited by the granite and trap veins, and numerous other cir- 
cumstances, form subjects highly worthy cf investigation. No 
