150 
THE GEOLOGIST. 
Nortli of Marlborough, where it is thick, tlie chalk-rock appears to have given 
rise to two escarpmeuts (an upper and lower one), in the chalk range. 
Fossils are usually rare in this bed; but Mr. J. Evans, P.G.S., collected 
several from it near Boxmoor ; and amongst them is the genus Belosepia 
(hitherto known only as tertiary) ; Baculitus, Nautilus, Turrilites, Solariumy 
Inoceramus, Parasmilia, and Ventriculites are here represented ; and the follow- 
ing species have been identified — Litorina monilifera and a new species, Pleuro- 
tomaria, sp. Myacites mandibula, Spondylus latus, Sp. spinosus, Rhynchonella 
Mantelliana, Texehratulata hiplicata, and T. semiglobosa. 
The fossils mostly have a lower-chalk character. Two species, Littorina 
monilifera, and Myacites mandibula, have not been noticed in England above the 
Upper Greensand. 
February 6, 1861. 
" On the Altered Rocks of the Western and Central Highlands." By Sir 
R. I. Murchison, E.R.S., V.P.G.S., and A. Geikie, Esq, E.G.S. 
In the introduction it was shown that the object or this paper was to prove 
that the classification which had been previously established by one of the 
authors in the county of Sutherland was applicable, as he had inferred, to the 
whole of the Scottish Highlands. The structure of the country from the 
borders of Sutherland down to the western part of Ross-shire was detailed, and 
illustrated by a large map of Scotland coloured according to the new classication, 
and by numerous sections. Everywhere throughout this tract it could be 
proved that an older gneiss, which the authors called " Laurentian," was over- 
laid nnconformably by red Cambrian sandstones ; these again unconformab'y 
by quartz-rocks, limestones, and a gneissose and schistose series of strata, as 
])reviously shown in the typical district of Assynt. Erom the base of these 
quartz-rocks a perfect conformable sequence was shown to exist upwards into 
the gneissose rocks, which is not obliterated by granite or any similar rock. 
The tract between the Atlantic and the Great Glen consists, according to the 
authors, of a series of convoluted folds of the upper gneissose rocks, until, 
along the line of the Great Glen, the underlying quartzose series is brought 
up on an anticlinal axis. A prolongation of this axis probably exists along 
part of the west coast of Islay and Jura, two islands which exhibit a grand 
development of the lower or quartzose portion of the altered Silurian rocks of 
the Highlands. 
Erom the line of the Great Glen north-eastward to the Highland border, the 
country was explained as consisting of a great series of anticlinal and synclinal 
curves, whereby the same series of altered rocks which occur on the north- 
west is repeated upon itself. One synclinal runs in a north-east and south-west 
direction across Loch Leven. The anticlinal of quartzose rocks that rises 
from under it to the south-east spreads over the Bredalbane Eorest to the Glen 
Lyon Mountains, where it sinks below the upper gneissose strata with their 
associated limestones. Ben Lawers occupies the synclinal formed by these 
upper strata, and the limestones and quartz -rock come up again in another 
anticlinal axis corresponding with the direction of Loch lay. The continuity 
of these lines of axis was traced both to the north-east and south-west. 
It thus appeared that the crystalline rocks of the Highlands are capable of 
reduction to order ; that the same folds and curves could be traced in them as 
in their less altered equivalents of the South of Scotland ; and that in what 
had hitherto appeared as little less than a hopeless chaos, there reigned a regu- 
lar and beautiful simplicity. 
In conclusion, Sir Roderick Murchison vindicated the accuracy of his published 
sections in the north-west of Sutherland, which had been approved after personal 
inspection by Professors Ramsay and Harkness ; and he gave detailed reasons 
for disbelieving the accuracy of the sections recently put forth by Prof. Nicliol, 
