354 
SILUEIA. 
[Chap. XIV. 
Forbes, whose residence at Christiania enabled him to contribute satisfactory 
information, clearly demonstrating the conversion of sedimentary Silurian strata 
into crystalline rocks replete with simple minerals *. 
To resume the history of succession. The ' Primordial ' fauna of Scandi- 
navia, which I long ago characterized as 1 the earliest zone of [then] re- 
cognizable life/ consists, in its lowest stage, of Fucoids only. The next 
zone contains the Graptolites, Shells, and Trilobites before alluded to, 
some of which are identical with fossils of our Lingula- flags of Britain, 
or the ' Zone Primordiale ' of Barrande. Its Trilobites have been elabo- 
rately described by Professor Angelin t, who has added much to our ac- 
quaintance with these fossils. Among the Crustacea of these beds (< Be- 
giones A, B' of Angelin), we recognize in Sweden several of the genera 
which characterize some of the lowest of the fossiliferous beds of Britain. 
The most plentiful of these Crustaceans are Agnostus pisiformis and many 
species of Olenus, of which last-named genus some species also occur in 
the black schists of our Malvern Hills (p. 45). 
Then the Swedish ' Regiones C and D ' of Angelin are, as in Norway, 
nothing more, as respects their fossils, than masses of Lower Silurian 
rocks (Llandeilo and Caradoc) as described in England and Wales, and 
which reappear in great force in the Bay of Christiania, Norway. They 
are specially identified by the abundance of Trilobites of the same genera 
as those in our British strata of this age, viz. Asaphus, Ogygia, Remo- 
pleurides, Trinucleus, Illaenus, Ampyx, &c. Many species of Trilobites 
and Mollusks of the two countries are identical, as shown by the preceding 
details. 
Having examined these Lower Silurian rocks over various tracts of 
Sweden and Norway, I can assure geologists that, rich as they are in fos- 
sils (so rich that they have enabled M. Barrande, as will soon be seen, to 
parallel every one of their stages, from the lowest upwards, with the 
' Primordial ' and succeeding zones of Bohemia), the whole of the lower 
Silurian of Scandinavia never much exceeds in vertical thickness about 
1200 feet ! And yet this mass is as complete in the development of life 
as the 30,000 feet of strata of the same age in Britain, which have been 
so much expanded by intercalations of igneous matter ! Nay, the general 
succession is essentially the same as in our islands ; for the Lower 
Silurian of Sweden and Norway is conformably overlain by a zone charged 
with Pentamerus oblongus, and passes up into shales and limestones 
which completely represent the Upper Silurian, particularly the Wenlock 
formation. 
And here, in respect to nomenclature, I may observe that the geologist 
who should seek to separate the Lower Silurian of Sweden and Norway 
from the Upper, and call the higher part only Silurian, would make a j 
distinction which could not be followed out upon any map; for these I 
* Quart. Journ. G-eol. Soc. vol. xi. pp. 166 &c. § Palaeontologia Suecica, pt. 1. 1852. 
