Geological Society. 529 



GEOLOGICAL SOCIETY. 



[Continued from p. 467.] 



May 6, 1857.— Colonel Portlock, R.E., President, in the Chair. 



"The Silurian Rocks and Fossils of Norway, described by M. 

 Theodor Kjerulf, and those of the Baltic Provinces of Russia, by Prof. 

 Schmidt, compared with their British Equivalents." By Sir R. I. 

 Murchison, V.P.G.S. &c. 



M. Kjerulf of Christiania, having communicated to the author 

 descriptive letters and illustrative diagrams of the relations and di- 

 mensions of the different strata of the Silurian rocks of the territory 

 of Christiania, as well as a series of their organic remains, — and Count 

 Keyserling having forwarded to him a memoir by Prof. F. Schmidt, 

 of Dorpat, comprising the results of an examination of the Silurian 

 rocks of the territory of Esthonia, Northern Livonia, and the Isle of 

 Oesel, — Sir Roderick in this paper brought an outline of these docu- 

 ments under the consideration of the Society, in order to show how 

 independent observers in other tracts have come to the conclusion 

 that the Silurian System as defined by them, as well as by himself, 

 forms a natural-history group, both as to its geological relations and 

 its zoological contents. He pointed out also that the Silurian 

 rocks of Russia and Scandinavia agree with those of Britain from 

 the Lingula-flags upwards to the Ludlow rocks inclusive. 



M. Kjerulf divides the whole Silurian series of his country into 

 three physical groups, viz. (in ascending order) the Oslo, the 

 Oscarskal, and the Malmoe groups ; and in these he recognizes four- 

 teen subdivisions. The lowest, or Lower Oslo group, including the 

 alum-schists with bituminous limestone, and resting upon unfossili- 

 ferous quartzites, the equivalent of the Longmynd rocks, represents 

 (though only 150 feet thick) the "primordial zone" of Barrande, 

 and the Lingula-flags and Stiper-stones of Britain. It contains the 

 Graptopora flahelUformis and Fenestrella socialis mixed with Lingulte, 

 as in Britain ; and with these occur the Agnostus pisiformis, Didymo- 

 grapsus geminus, and Orthis calligramma, which in the Silurian 

 region of Britain are found in the true Llandeilo group. Hence, the 

 author observes, that, in extending our survey, it is impracticable 

 in general classification to separate the Lingula-flags or " zone 

 primordiale " from the Lower Silurian rocks. The Upper Oslo 

 group, with graptolites and orthoceratites, represents the Llandeilo 

 rocks. The Lower Oscarskal groups are referred to the true 

 Caradoc or Bala series, as now defined. The Upper Oscarskal and 

 part of the Lower Malmoe group (comjjrising the Pentamerus rocks) 

 represent the Llandovery rocks of South Wales, forming a transition 

 from the Lower to the Upper Silurian rocks of Murchison. The 

 equivalents of the Wcnlock and Lower Ludlow rocks succeed in the 

 Middle and Upper members of the Malmoe group. 



The Silurian rocks of the Baltic provinces of Russia (as indicated 

 in a maj)) are represented by Prof. Schmidt as consisting essentially 

 of a series of strata following each other in ascending order, at slight 

 angles of inclination to the south, constituting zones trending gene- 

 rally from east to west, and passing under the Devonian rocks of 



