118 
THE GEOLOGIST. 
character when the same rocks are follov/ed southwards or south-south-west upon 
their strike ; and the author stated his belief, that not only may the regularly 
bedded limestones which are intercalated in the chloritic and quartzose rocks of 
Dumbartonshire be classed with some of the oldest of those stratified masses 
which, like the limestones of Sutherland, are unquestionably of Lower Silurian 
age, but that the vast and evidently overlying masses of mica-schist and 
qnartzose gneissic flag-rocks of the Breadalbane district may be some day found 
to be simply the prolongations of the micaceous flagstones of the North-western 
Highlands above alluded to, as overlying the quartz rock and fossiliferous lime- 
stone ; further, that in the still higher limestones and schists seen on the banks 
of Loch Tay, we may speculate on the existence of the equivalents of younger and 
higher strata than any which are observed in the Northern Counties. 
After some observations on the truly stratified condition of these micaceous and 
gneissose schists (younger gneiss) of the Highlands, Sir Roderick proceeded to 
the consideration of the " Old Red Sandstone of the North east of Scotland ; " 
defining the tripartite division of this great series, and demonstrating that the 
beds with Cephalaspis Lycllii and Pteryjotus Anylicus of Forfarshire really lie at 
the base of the series, and are certainly of greater antiquity than the bituminous 
fossil -bearing schists of Caithness. This division is in accordance with the 
relations of the deposits of the Devonian period, as seen in Devonshire and Ger- 
many ; though the lowest member of the Old Red of Scotland has no representative 
in the Devonian rocks of Russia. The Caithness flagstones were described as 
being in the middle of the series ; whilst the underlying conglomerates and sand- 
stones were shown to be the true equivalents of the Cephalaspis-beds of Forfar- 
shire, and of the lower cornstone-strata of Herefordshire, which there graduate 
downwards, through the tilestones, into the uppermost Silurian rocks of Lud- 
low. 
The Old Red rocks of the North Highland were described in more or less detail 
by the author, who showed that the group, as seen in Caithness and the Orkney 
Islands, is composed of — 1st, lower red conglomerate and sandstones ; 2nd, grey 
and dark-coloured flag-stones and schists, both bituminous and calcareous (this 
portion being in Elginshire and .Murrayshire represented by cornstones) ; and 
3rd, upper red sandstones. The North Scottish Old Red contains one great 
inferior portion which has no representative in the Devonian rocks of some foreign 
countries, though it is completely represented in all its parts in other tracts both 
of Britain and the Continent. 
Having next described the conditions under which many of the species of fish 
(at least twenty-one) found fossil in Caithness and Cromarty occur in Russia 
commingled with the middle Devonian mollusks of Devon, the Boulonnais, and the 
Rhine ; and, having pointed out that the lowest member of the Devonian series, 
with its Cephalmpides, is wanting in Russia, Sir Roderick insisted on the import- 
ance of the Devonian series in the scale of formations, and on the fact that the 
Old Red conglomerates, ichthyolitic schists, and cornstones, with the overlying 
sandstones of Scotland and Herefordshire, fully represent in lime the Devonian 
rocks of the south of England and the continent, so full of corals, crinoids, and 
marine mollusks. 
Some brief observations on the Newer Red Sandstone of the West Coast of Ross- 
shire, and the Lias and Oolitic deposits of the North of Scotland and the Western 
Isles, concluded this paper. 
A series of the Fossils from Durness was exhibited in illustration of the me- 
moir, which was also illustrated by a new geological map of the Northern High- 
lands, and by a large general section across the North of Scotland. 
At the meeting, a crystal of transparent calc-spar from Iceland, of unusual 
size, was exhibited by Prof. Tennant, F.G.S. 
On the 19th Feb. (anniversary). Major-Gencral Portlock, the President, read 
a lucid and comprehensive addre s, in which, after the obituary notices of late 
eminent geologists, a masterly exj osition was given of geological investigations, 
