REVIEW OF THE SILURIAN FOSSILS OF RUSSIA. 
35 * 
lineatus, Tentaculites annulatus, Calymene Blumenbachii var. pulchella, Terebratula diadonta (Dalm. and Sil. .Syst.), 
T. tumida, T. canalis (Sil. Syst.), Atrypa deprexsa (Sil. Syst.), A. reticularis or A. affinis (Sil. Syst.), A. didynia, 
Orthis orbicularis (Sil. Syst .), Belt hyris sulcata (His.), Avicula reticulata (Ilis. and Sil. Syst.), Mya rotundata ? 
(Sil. Syst.), Cardium striatum (Sil. Syst.), Cyathocrinites pinnatus. 
This list, prepared by so good a palaeontologist as M. Pander, at once establishes 
the true age of the chief limestone to be Upper Silurian, and shows that it is, as 
nearly as possible, the equivalent of the Wenlock limestone. But the evidence is 
rendered more decisive when he tells us, that the deposit containing these fossils 
is there surmounted by another calcareous band in which occur the very group ol 
organic remains that characterize the Upper Ludlow rock of the British Isles, and 
certain tilestones which, though first classed as the base of the Old Red Sandstone, 
are, as we have said, now considered to constitute the highest stratum in the Silu- 
rian system 1 . In these beds the Terebratula reticularis (vel prisca ), T. lacunosa 
(His.), and T. didyma (Sil. Syst.), are associated with a Spirifer (we believe the 
species to which we have adverted in the uppermost Silurian band of Norway and 
Sweden), and with these are the two very characteristic British species of the tile- 
stone, Turbo Williamsi and Turritella obsoleta. 
These evidences are, therefore, quite decisive in proving, that the chief deposits 
of the isles of Oesel and Dago are of the same age as those of the Isle of Goth- 
land ; and that, distinct from the palaeozoic rocks of the mainlands of Sweden on 
the one hand, and of Russia on the other, they truly represent the Upper Silurian 
group of the British Isles. 
As geologists we must further express our belief, that the phenomena ol suc- 
cession in these regions are thoroughly well explained by the signs of eruption and 
elevation which we have already described. The protrusion to the surface of 
igneous rocks in the fissure of the Gulf of Finland and all along the north-eastern 
frontier of the palaeozoic deposits of Russia, as well as the continent of Sweden, is 
Amply sufficient to satisfy our minds respecting the cause whereby the most ancient 
sea-bottoms in which animals lived, were raised into lands on either side oi the 
Baltic, and put beyond the influence of those marine conditions under which the 
Isles of Gothland, Dago and Oesel were subsequently formed in an ancient geolo- 
gical trough. 
The ascending succession of strata which we have described in passing from 
east to west in the Russian Baltic provinces strongly favours this view, and leads 
1 See ante, note 1, p. 13. 
