fteports and Proceedings. 39 
thus, Ctenacanthus, Pleuracanthus, and Orthacanthus—this last 
genus has not been hitherto recorded from this district. These 
large spines and some teeth and other Fish-remains were found in 
shale, forming the roof of the Splint-coal in the Cambuslang district, 
south-east of Glasgow. The chairman exhibited a series of speci- 
mens illustrating the fauna of the Old Red of Forfar, which he owed 
to the kindness of James Powrie, Esq., of Reswallie; also a photo- 
graph, by Mr. Powrie, of a group of these fossils. Mr. Crosskey 
also exhibited specimens of the Laurentian Gneiss of Sutherland, 
which is claimed by Sir R. Murchison as the oldest rock in the 
British Islands, and remarked upon their hornblendic character, and 
their dissimilarity to the gneiss of the Argyllshire district,—a view 
which was confirmed by Mr. Young. The secretary exhibited a 
variety of copper-ores, including the new and rare Cornish mineral 
Langite, from the collection of John Tennant, Esq., Garngad Hill, 
by whose kindness he had been enabled to exhibit it. 
2. Mr. Youne then drew attention to a number of-very interesting 
local varieties of sandstones, from the Old Red and Carbonifer- 
ous formations, and, with one or two exceptions, from the neighbour- 
hood of the city. After describing the general character of our 
sandstone rocks, Mr. Young referred to some curiously blotched and 
circular-spotted sandstones from the Old Red near Dumbarton, 
which had long puzzled geologists and others as to how the per- 
oxide of iron had been discharged fromthe stone ; but as yet no 
satisfactory explanation had been given as to the real cause of the 
discoloration. A white sandstone from the same locality was full of 
black spots of bituminous matter, which stain the stones very much 
as if they had been sprinkled over with drops of coal-tar ; and he 
said it was a very difficult question to decide whether these spots 
were due to the decay of organisms—no traces of which, however, 
can now be discovered in them, or have been produced by some other 
unknown natural cause. He next remarked on the specimens of 
black, brown, and striped sandstones from the Carboniferous for- 
mations, that owed their colour to bituminous matter, which had 
either been mixed with the sand by deposition along with it, or by sub- 
limation from neighbouring coal-strata, penetrating the porous sand- 
stone. Some of these contain a considerable quantity of volatile 
bituminous ingredients which can be readily distilled from the stone. 
In others, where the bituminous sandstone has been overlain by, or 
in contact with, igneous products, the bitumen had been converted 
into anthracite, and gives off no gas or flame; all of these sand- 
stones become white by burning. One curious and unique variety 
of striped sandstone from Newton, near Cambuslang, excited much 
interest from the great regularity of its markings. Mr. Young 
stated that the base of this variety was brown, but at nearly regular 
intervals of fully one quarter of an inch, it alternates with thin, 
sharply defined, regular layers or stripes of white, of about half a line 
only in thickness, giving an almost artificial appearance to the stone. 
He did not consider this striping to be caused by the deposition of dif- 
ferent coloured sands ; for it is obliterated by burning ; and the stone 
