118 



THE GEOLOGIST. 



clmracter when the same rocks are followed 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 Lyellii and Pterygotus Anglicus 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 moUusks of Devon, the Boulonnais, and the 

 Rhine ; and, having pointed out that the lowest member of the Devonian series, 

 with its Cephalaspides, 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 time the Devonian 

 rocks of the south of England and the continent, so full of corals, crinoids, and 

 marine moUusks. 



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 largo 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 10th Fob. (anniversary). Major-Geueral Portlock, the President, read 

 a lucid and comprehensive address, in which, after the obituary notices of late 

 oniinout geologists, a masterly cxj osition was given of geological investigations, 



