230 
TliE GT.OLOaiST. 
One of Sir Eoclerick's principal objects in exploring this region was to 
convince himself, if possible, of the existence of a fundamental gneiss of as 
high antiquit}' as the Laurentian rocks of Canada and Scotland, and of 
the truth of M. Giimbel's view of the distinction of the gneiss into older 
and younger ; but, after a survey of the whole district, he was unable to 
distinguish any order of superposition between its two members, the so- 
called 3'ounger gneiss, in one extensive tract near the Danube, dipping, 
according to M. Giimbel, under the older ; and their variable strike ren- 
dered it as difficult to judge by that character as by their dip, its direction 
in some places being at right angles to what it is in others. For the pre- 
sent, therefore, though with the greatest respect for the labours of 
Giimbel, he considers the gneiss-rocks to constitute one great series, it 
being certain that the two varieties are not separated by any dijfferent in- 
tervening sediment, as in the north-west of Scotland. 
A clear illustration of the whole ascending succession is afforded by the 
order of superposition exhibited in M. Giimbel's section from Hof to Selb, 
a distance of about seven or eiglit miles. Gneiss is there seen resting 
against granite, and passing ap into mica-slate underlying concretionary, 
quartzose, chloritic masses, which form the base of the Urthonschiefer. 
This primary clay-slate is followed by quartzites and black roofing-slate, 
in the latter of which the fossils of the Silurian primordial zone of Bar- 
rande occur, and ultimately by other Silurian, Devonian, and Lower Car- 
boniferous strata in conformable succession, the latter passing conformably 
upwards into mountain limestone, which is shown to be quite unconform- 
able to the Upper Carboniferous of Germany. In the remaining north- 
west portion of the section the strata are repeated in inverted succession, 
luiving been dislocated by the intrusion of igneous rocks. 
Sir Eoderick next adverted to the question of the parallelism of the 
Silurian rocks of Bohemia with those of Britain, pointing out that the 
Austrian Geological Survey, whose new map he exhibited, had adopted, 
for this occasion only, the colours used by the Geological Survey of Great 
Britain ; and he stated his belief that too close a parallelism bet^^ een the 
subformatious had been attempted, and that the parallelism of such large 
groups only as Lower and Upper Silurian, as proposed by Barrande, with 
a possible interpolation of " Middle Silurian," could be maintained. 
The author then contrasted the absence of Devonian and Lower Car- 
boniferous rocks, coupled with the full development of Lower and Upper 
Silurian life, in Bohemia with the fuller and unbroken succession in 
Bavaria. He concluded by observing that the conformable succession of 
strata in Bavaria and other tracts shows the existence of beds which 
bridge over the gaps, represented by unconformities, that occur in the 
British series ; and pointedly advertecl to the tw o facts, that the enormous 
thickness of clay-slate beneath the primordial zone, though unaltered 
over large areas, had afforded no vestiges of life, and that the transitional 
groups of strata uniting two great systems had not afforded in any country 
a link connecting one class of animals with another. 
2. " JN'otice of a Section at Mocktree." By R. Lightbody, Esq. 
The lower portion of this section was stated to exhibit the Aymestry 
limestone, with its characteristic honeycomb structure, and showing at its 
upper limit a basin-shaped depression containing beds of sandy day depo- 
sited parallel to its sides, and unconformable to the Aymestry limestone, 
though at a little distance from the trough this unconformity disappears. 
These argillaceous beds contain Lower Ludlow fossils, though they over- 
lie the Aymestry limestone ; the author consequently proposes that the 
latter term should no longer be used as a separate subdivision. He also 
