Chap. XV.] 
SILUKIAN FOSSILS OF BOHEMIA. 
377 
In short, about 2735 species of fossils have already been obtained through 
the labours of this naturalist in working out the rich materials of his Silurian 
Basin j and as in Britain and other parts of the world, so in Bohemia, the 
most assiduous researches, aided by the microscope, have failed to detect the 
trace of a vertebrated animal below the uppermost Silurian rocks. In the two 
highest bands of these, and notably in the uppermost only, has M. Barrande 
obtained fragments of Fish-bones. It is further remarkable that he has found the 
peculiar Crustacean Pterygotus, ranging, as it does to a great extent in England, 
through the Upper Silurian rocks (pp. 237 &c). See also Sil. Syst. pi. 4, and 
p. 606. 
The geologist who compares this edition of 'Siluria' with the first, will 
have already perceived, p. 47 est seq., that in the years which have elapsed, many 
new or additional fossils have been detected in the lowest stages of the Llandeilo 
rocks, chiefly in the Silurian region of England and Wales, as well as in the 
crystalline quartzites and limestones of Sutherlandshire (p. 165). 
Now, just in this interval of time has M. Barrande discovered, at the same 
horizon in his Silurian Basin of Bohemia, a fauna which much resembles that of 
the same old British zone. Thus iEglina prisca, Barr., resembles very nearly 
iEglina binodosa, Salter, of the Stiper Stones (p. 48) ; whilst the Redonia of 
Rouault has its representative in the British form (fig. 2. p. 48) ; and Ribeiria 
pholadiformis, Sharpe, which characterizes the Lower Silurian of Portugal, and 
is matched by our R. complanata (fig. 3. p. 48), makes its first appearance in 
Bohemia in this Stage. Let us also mark that here, as in Shropshire, Graptolites 
and Orthoceratites are associated in the same zone with the above-mentioned 
Mollusca, and that one of the Bohemian Orthocerata has a striated surface simi- 
lar to that of our Orthoceras Avelinii (p. 48. fig. 4). 
But notwithstanding the unmistakeable analogy between the ' Second Fauna' 
and that of the Llandeilo and Caradoc formations of England, M. Barrande is of 
opinion that it is impossible to identify any one of his subdivisions with any 
particular English stratum. He believes this applies equally to his 1 Zone Pri- 
mordiale ' and to his ' Third Fauna ' (Etage e). At the same time he points out 
that the successive apposition of the fossils is essentially the same, but with some 
notable differences. Thus, among the Cephalopods, the first Cyrtoceras appears in 
Wales in the Tremadoc Slates ; there are six or seven species in the Llandeilo 
beds and two in the Caradoc formation. In Bohemia, on the contrary, there is 
no trace of a Cyrtoceras in all the Second Fauna (Etage d) to represent the 
British Llandeilo and Caradoc fossils, though there are two species in the 1 Co- 
lonies.' Again, Orthoceras vaginatum, or its representative, with a large mar- 
ginal siphon, which occurs in the British Caradoc, is only found in the very 
lowest bed of Etage d — that is, quite low in what we may consider to be the 
equivalent of the Llandeilo rocks. Whilst, therefore, the chief Lower Silurian 
formations are the same in both countries, the details of the development in each 
differ materially. In Britain we as yet know of no species which mounts up 
from the Lower Llandeilo to the Llandovery rocks ; but in the Bohemian basin 
nine or ten species of the lowest band of Etage d Q Second Fauna'), after disap- 
pearing in the three overlying bands, reappear in the uppermost strata. M. Bar- 
rande in his work on the ' Colonies ' of fossils, points out with great effect the 
recurrence of the same phenomenon in the Upper Silurian, i. e. his ' Third 
Fauna,' and says that the same thing occurs in other countries. 
M. Barrande has also met with another link which binds together the northern 
type of Russia, Scandinavia, and England with that of Bohemia, in a species of 
