1815.} Geological Society. ‘141 
allied to green-stone, passing sometimes into syehite, sometimes 
containing glassy felspar and hyperstene, and sometimes composed 
merely of quartz and hornblende. It is traversed throughout by 
dykes of basalt, in some places approaching to pitch-stone, and 
appears to rest on a very compact grey quartzy sand-stone, which 
does not contain shells, and like the superincumbent trap, is tra- 
versed by veins and dykes of basalt. 
Adjacent to the Cuchullin is another group, called the Red 
Mountains, of lower elevation than the former, presenting rounded 
outlines, and so covered with fragments in a state of decomposition, 
that the massive rock can rarely be perceived. The chief constituent 
ingredient of these mountains is flesh-red felspar, passing into clay- 
stone, and containing a small and variable proportion of hornblende 
and quartz. This rock, like that of the Cuchullin, is also traversed 
by veins of trap, and probably by veins of granite. 
The northern portion of the island consists for the most part of floetz 
trap in beds approaching to horizontal, alternating with sand-stone, 
and presenting seams of basaltic coal generally broken, imperfect, and 
of little extent. This trap offers the usual varieties, namely, basalt, 
either perfect, or approaching to wacke, green-stone, and amygda- 
Joid. ‘This latter variety contains nodules of steatite, balls of fila- 
mentous mesotype, crystallized mesotype, chabasite, and occasion- 
ally stilbite and ichthyophthalmite. In some parts the shale and 
sand-stone adjoining the trap are indurated, and more or less altered, 
the former in particular being converted into lydian-stone and 
botryoidal schist. The whole of the eastern shore of Strathaird 
exhibits one continuous cliff of blue compact lime-stone, split by 
numerous fissures, and hollowed out into caves. 
At Kilbride, near Loch Clapin, another lime-stone district occurs, 
the connections of which it is very difficult to ascertain. This lime- 
stone is unstratified, contains no organic remains, is of a granular 
structure, and is in many places a perfect marble, more or less 
coarse in its grain, of a white, blue, and yellowish-green colour 
(this latter from an intermixture of serpentine), and applicable to 
various uses in ornamental architecture. This lime-stone ceases 3 
mile or two short of Bradford; and on the shores of this latter 
water another formation of lime-stone, totally distinct from the 
other, makes its appearance. ‘This forms thin beds, alternating 
with sand-stone and shale, is highly bituminous, and contains 
annoni#, ammonit#, and other shells, and is traversed by trap 
veins. 
Between Loch Oransa and the northern part of the shore near 
Bradford is a tract of quartz rock, which also occurs in other parts 
of the district of Clate, accompanied by various primary schistose 
tocks, and intersected by veins of trap. 
A paper by J. Williams, jun. Esq. of Scorvier, describing the 
mine of Huel Peever, was read. 
The tin vein of Huel Peever, in the parish of Redruth, in con- 
sequence of its intersection by cross veins, by the underlie of a 
