IN GNEISS IN ROSS-SHIRE. 
125 
Asphaltum, Bitume solkle of Haiiy, the Slaggy mineral 
pitch of J ameson. 
Its external characters, according to Professor Jameson, 
are : Colour black ; occurs massive, disseminated, sometimes 
globular, reniform, and stalagmitic : externally and inter- 
nally, resplendent and shining; lustre resinous; fracture 
conchoidal, soft, opaque^ sectile. It occurs in veins, and 
in reniform and imbedded masses, in secondary limestone 
in Fifeshire, in clay ironstone in East Lothian, in veins 
at Houghmond Hill in Shropshire, and in mineral veins 
in Cornwall. According to Phillips, it varies from brown- 
ish-black to black ; it occurs massive, with a conchoidal 
fracture, and shining resinous lustre, and it is opaque and 
very brittle; specific gravity 1 to 1.6. By combustion, it 
leaves a small quantity of ashes. It consists chiefly of bi- 
tuminous oil, hydrogen gas, and charcoal ; the last is in 
much greater proportion than in elastic bitumen. Oxide 
of iron, and two or three of the earths, sometimes consti- 
tute very small proportions of it. It is found in the Pa- 
latinate, in France, in Switzerland, in large strata in Al- 
bania, and in large pieces on the shores and floating on the 
surface of the Dead Sea, It abounds in Trinidad and 
Barbadoes. In the former, it occurs in a vast lake three 
miles in circumference, called the Pitch Lake ; the thick- 
ness of which is yet unknown. 
Thus, Gentlemen, it appears, that, before this discovery, 
we were not aware of the presence of Asphaltum in any of 
the Primitive rocks of Scotland ; and, with the exception of 
the Carharack Vein in Cornwall, where it is found accom- 
panying yellow copper, we were not aware of its occur- 
rence in any of the primitive rocks of Great Britain. This 
Scottish vein is found in gneiss, in the Hill of Castle Leod ; 
it runs nearly perpendicular from the horizon, and is not 
above 1 J or 2 inches in thickness. 
