500 
THE GEOLOGIST. 
Now, although the Arbroath paving- stone, and the grey rocks ranging to the 
north of Dundee, inuc)i resemble the uppermost Ludlow rock, they contain the 
Cephalaspis Lyellii, and if, therefore, classed with the Devonian rocks, they must, 
under every circumstance, be viewed as the very base of that natural group. It 
follows, therefore, that certain conglomerates on the flanks of the Grampians, 
■which underlie all those grey rocks with Pterygoti and Cephalaspis, can no longer 
be united as they have been with the Old Red or Devonian, but must represent 
some portion of the Silurian system. In speaking of the lowest member of the 
Old Red Sandstone, as characterised by the Cephalaspis Lyellii, the author ex- 
pressed his conviction, that in the north-eastern Higlilands and Caithness the zone 
is represented by the vast thickness of thin-bedded red sandstone and conglomerates, 
which had been already adverted to as lying beneath the Caithness flags. 
The author, who had recently visited Dura Den, in Fifeshire, in the company 
of Lord Kinnaird and the Rev Dr. John Anderson, whose work on that beautiful 
tract is well known to geologists, declared that there ciuld be no doubt whatever 
that the yellow sandstones of Fife pertain truly to the Old Red group, are entirely 
subjacent to the lowest carboniferous sandstones, and are of the same age as the 
upper yellow sandstones of Elgin. A drawing, prepared by Lady Kinnaird (the 
splendid specimen being in the museum at Rossie Priory j, of the fossil fish Holo- 
ptychius nobilissimus, nearly three feet in length, which was found on the occasion 
of this visit on the property of Mrs. Dalgliesh, was exhibited ; and as this species 
abounds in the lower and red portions of the deposit, and also occurs in the over- 
lying yellow sandstones, associated with Holoptychius Anderson! and H. Flemingii 
of the latter, the age of the deposit is clearly substantiated. In conclusion, Sir 
Roderick said that this communication must only be considered as a rehearsal of 
what was to be done with more effect next year at Aberdeen, when further obser- 
vations migh V lead him either to confirm or modify some portion of his views. In 
the meantime, the great fundamental reform of the North Scottish series, proving 
the ascent from rocks on the west coast, which are unquestionably older than any 
in England and Wales, to the much younger " Old Red Sandstone '' of the east 
coast, is firmly established. 
The communication was illustrated by several geological maps, including an old 
one coloured by himself 31 years ago, the maps of M'Culloch, Nicol, and Knipe, 
and a map of Sutherland which the author coloured this summer. Besides large 
diagrams, there were sketches of the west coast of Sutherland by Miss Charlotte 
Dempster. 
Mr. Page also communicated a paper on Scottish Geology, under the title of 
" The Relations of the Metamorphic and Older PaliBOzoic Rocks of Scotland." 
Under the same head. Dr. Anderson made a communication "On the Fossils 
and Yellow Sandstones of Dura Den." This interesting paper led to considerable 
discussion, of which we can only give a very abridged account. 
Dr. Anderson said — " I shall only say a very few things, and that as briefly as 
possible. Sir Roderick Murchison began his lucid and elaborate statement by a 
reference to Cape Wrath, where, after a day of geological toil, he slept, I doubt 
not, soundly, in what Maculloch describes ' as the land's end of Scotland's wildest 
region, the advanced post of Scotland's wildest seas.' I shall now conduct you to 
the quiet scenes of the south, where, in the terras of classic mythology, the vale of 
Ceres, lately covered with the golden fruitage of autumn, terminated the fossil- 
iferous deposit he was now to describe. I am relieved, however, of much of my 
task respecting tlw, jmilion of this deposit in the series, in consequence of what 
had been stated by Sir Roderick, who declares it now, as he did when he formerly 
visited the spot, to be a member of the true Old Red Sandstone, and to have no 
geological connection with the Carboniferous system above ; and I am happy also 
to say that I have no opponent upon this point seriously now to contend against, 
nor to be confronted by any Professor Nicol called upon to unlearn the lessons 
which I myself had taught him. Much error, however, still prevails regarding 
the Yellow Sandstone, botli as to its true mineraiogical characters and its 
geognostic relations. In Ireland, it seems to be utterly misunderstood by Sir 
llicliard Griffith, who, in his comiiiunio itioii to tfiis section last year at Dublin, 
