ANNIVERSARY ADDRESS OF THE PRESIDENT. 163 



look forward to receive from Sir H. de la Beclie and his fellow- 

 labourers in the Geological Survey of Great Britain, we shall pos- 

 sess a very full and correct knowledge of these older sedimentary 

 deposits, and the igneous rocks with which they are associated, and 

 therefore of the most remote periods of geological history ; and we 

 may perhaps then indulge in a little excusable national vanity of 

 possessing another standard with which the structure of extensive and 

 distant regions of the earth will be compared, in addition to what we 

 already have of many of the palaeozoic and secondary formations. 



A paper by ('aptain Bayfield read before us last April, and pub- 

 lished in November in our Journal, gives us much important infor- 

 mation on the Silurian rocks that prevail to a great extent in Canada ; 

 and we are indebted for a more accurate knowledge of the same class 

 of rocks in the Isle of Man to the Rev. J. Gumming, in the first part 

 of a description of that island, read last June. 



We learn from the ' Geology of Russia,' that both in that coun- 

 try and in Scandinavia, a series of ancient deposits cover a great 

 tract of country, which, in all their great features, and often in their 

 minute characters, are identical with the Silurian series of the Bri- 

 tish Isles, and that they are equally divisible into two distinct groups, 

 and are also overlaid by a true Devonian formation. In the cen- 

 tral and southern parts of the continent of Sweden the Lower Silu- 

 rian rocks only occur, but the adjoining islands of Oesel, Dago and 

 Gothland are mainly composed of Upper Silurian rocks, affording 

 even better types than Wenlock or Dudley. Describing the rocks 

 near Katchkanar, on the eastern flank of the Urals, Sir R. Murchison 

 says, " The banks of the river Is are composed for a considerable di- 

 stance of white limestone, thickly tenanted by large Pentameri, some 

 Trilobites, and shells which we hailed as true Silurians, and worthy 

 of the very region of Caractacus. We were enchanted when we 

 discovered myriads of them undistinguishable from the Pentamerus 

 Knightii ; so that seated on the grassy banks of the Is, we might for 

 a moment have fancied ourselves in the meadows of the Lug at 

 Aymestry," Of the Lower Silurian fossils of Russia a few only are 

 absolutely identical with forms of the same age in the British Isles ; 

 but the mass of them is essentially the same as that of the main land 

 of Scandinavia ; which region being intermediate between England 

 and Russia, is found to contain a considerable number of forms 

 common to deposits occupying the same position in both the other 

 countries. In the lowest part of the Lower Silurian rocks that 

 skirt the southern shores of the Baltic, a grit occurs so abound- 

 ing in a minute shell, the Ungulite or Obolus (which has a great 

 affinity to the Lingula), as to form entire beds. Here we have a 

 parallel to those beds in the Silurian series of the British Isles, 

 abounding so copiously in the Lingula attenuata. It is also a parallel 

 to beds occurring at a far more distant point, on the opposite side 

 of the Atlantic. Mr. Lyell, in describing the Potsdam sandstone, 

 the lowest member of the Silurian series in North America, as it 

 occurs on Lake Champlain, says, " In many places this most ancient 

 of the fossiliferous rocks of New York is divided into laminae by the 



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