Chap. XIV.] PALAEOZOIC SUCCESSION IN NORWAY. 
353 
a detailed map and drawings of many fossils, showing that the lowest fossilife- 
rous strata contained Graptolitidse with the well-known Lower Silurian Brachio- 
pods Orthis callactis, Atrypa lenticularis, Dalm., Lingulella Davisii, together 
with Olenus and other Trilobites. Lastly, in the same year, MM. Kjerulf and 
Tellef Dahll brought out a geological map of all Southern Norway, accompanied 
by many sections *. In this last work, as in the preceding publications, the 
varied geological features have been laid down upon the same topographical 
map on which the late Professor Eichwald delineated the structure of Norway. 
All geologists who make the comparison will therefore see at once what vast 
advances have been made in the last twenty-three years, or since I first applied 
(in 1844) the Silurian classification to the rocks of that kingdom. 
The general'ascending series, as worked out and as exhibited in the map, tables, 
and sections of Kjerulf and Tellef Dahll, is as follows : — 
1. Fundamental rocks of gneiss, and quartzose, hornblendic and micaceous 
slates, with some bands of crystalline limestone. These may represent the 
Laurentian rocks of North America and the North-west of Scotland. 
2. Talcose schists and other metamorphosed rocks, with dolomites. These the 
authors now refer to the so-called ' Taconic' rocks of North America j but as the 
latter have been ascertained to be nothing more than metamorphosed integral 
parts of the ordinary Lower Silurian, the use of this term is misplaced f . These 
masses seem, indeed, to occupy the very place of the ' Primordial ' Silurian Zone 
of Britain and Bohemia ; for in parts they contain the same Trilobites and well- 
known common Brachiopods of the ordinary Lower Silurian rocks, by which 
they are overlain conformably. 
3. Great mass of the Lower Silurian rocks, overlain in many places by Upper 
Silurian, which, as before stated, is surmounted by Old Red Sandstone. 
In addition to this description of all the older stratified rocks, MM. Kjerulf and 
Tellef Dahll have laid down upon their map the outlines of eight varieties of ig- 
neous rocks, from the oldest granites of the icy Dovre-Feld, through a succession 
of molten rocks of different ages, including gabbro and syenite, up to the por- 
phyries and quartzose porphyries. They have also indicated by separate colours 
the chief events in the series of glacial changes, from the most ancient moraines 
of land-glaciers, through the succeeding operations of ice, whether in connexion 
with the deposition of gravel, sand, and sea-shells, or the transport of erratic 
blocks, followed by great alluvial accumulations. Such labours are worthy of 
all praise. 
Besides the clear order of superposition of the various Silurian rocks and 
their identification by fossils, M. Kjerulf has further shown how different 
members of the series have been here and there metamorphosed into crystalline 
gneiss. The numerous points at which the sedimentary formations have been 
pierced by eruptive rocks long ago suggested to the late Professor Forchhammer 
and myself a sufficient explanation of such conversions %. 
This subject has, indeed, been since worked out in some detail by Mr. David 
* 4 Geologische Karte,' Kjerulf and Tellef Dahll : 
Christiania, 1858-65. 
t Not only Sir W. Logan and the Canadian 
Surveyors, but, as far as I know, all American 
geologists now admit that the ' Taconic ' schists 
and slates of Emmons are simply the metamor- 
phosed representatives of the Quebec (Lower Si- 
lurian) Group of those regions. Judging, however, 
from their fossils, I apprehend that in Nor- 
way the rocks which Kjerulf and T. Dahll have 
called 4 Taconic ' are simply a northern extension 
of the ' Primordial ' Silurian rocks of Barrande, 
which in North Wales exhibit a great expansion 
as Lingula-flags. In Norway, indeed, they are 
demonstrated to bean integral part of the Silurian 
system by containing Graptolitopora (Dictyo- 
nema), together with Olenus and common Lower 
Silurian Brachiopods. According to my view, these 
beds, ranging into the central mountains of Nor- 
way, are proved by their fossils to be simply ex- 
pansions of the much more diminutive Alum-sl»tes 
of Sweden, Bornholm, and Norway. 
I Quart. Journ. Geol. Soc. vol. i. pp. 470, 474, 
&c, and Kussia-in-Europe, vol. i. p. 14, note. 
2 A 
