1857.] MURCHISON — SILURIAN ROCKS OF SCANDINAVIA. 53 



my distinguished associate, De Verneuil, have, however, many specific 

 equivalents in the Lower Silurian rocks of that Bohemian basin which 

 has been rendered classic through the works of M. Barrande. 



Count Keyserling further recalls my attention to the fact, that 

 the Ural Mountains and Siberia fall into the same category. This 

 comparison, which was to some extent shadowed forth in the work 

 'Russia and the Ural Mountains,' published in 1845, has been stri- 

 kingly confirmed by the researches of M. Griinewaldt into the cha- 

 racters of the fossils of the eastern flank of the Ural Mountains near 

 Bogoslofsk (lat. 61°). Again, M. Hofmann concludes his Siberian 

 work in terms which show, that the parallel was suggested eleven 

 years ago by Keyserling, as a result of his researches and comparisons 

 in the Northern Ural. In short, my coadjutor long ago directed 

 notice to the fact, that, both in palseontological contents and litho- 

 logical characters, the Silurian rocks on the eastern side of the Ural 

 Mountains were dissimilar to those of European Russia and Scandi- 

 navia. Metamorphism alone, he always contended, could not explain 

 this essential difference. The conditions of life, he added, had been 

 one thing in the seas that occupied the Siberian area, and another in 

 * the waters which covered the low countries of western and southern 

 Europe during the Silurian epoch. 



Since that time, this distinction of the varying faunas in contem- 

 poraneously formed basins, separated from each other during the 

 older palaeozoic period, has been abundantly developed by M. Bar- 

 rande, who has well shown the specific distinctions between the animals 

 which inhabited respectively the regions of Bohemia and Scandinavia 

 during the Silurian era. 



It is to the similarity, on the contrary, of the organic remains in 

 the northern zone of Silurian rocks, which extends over so vast a 

 space, that attention has been mainly directed on this occasion. 



Finally, let me state, that another chief object I have had, in 

 bringing together the observations of Count Keyserling, Professor 

 Schmidt, and M. Kjerulf, with comparisons of my own, is to demon- 

 strate that in Scandinavia, as in Russia in Europe, Silurian rocks, 

 both Lower and Upper, and copiously charged with characteristic 

 organic remains, form a united and unbroken whole ; and that, 

 whether viewed palseontologically or geologically, they exhibit 

 throughout those northern European regions, and in a very small 

 compass, a natural-history system quite as complete, and more 

 easily understood, than their much more expanded, highly varied, 

 and dislocated equivalents in the British Isles. 



