132 Murcluson and Verneuil on the Geological Structure 



Russian Lapland, the boundary of which they coasted, confined their 

 attention to the ascending order of the strata, wliich is clearly exhibited 

 on the banks of the WolkofTand at other places. 



2. Old Red, or Devonian System. — That the inferior strata are the true 

 equivalents of the Silurian sj'stem, was determined not onl}'- by their 

 aspect and fossil contents, but by their being overlaid by other rocks 

 which are completely identical with the " Old Red System" of the Bri- 

 tish Isles, as defined by Mr Murcluson.* This system is of great extent 

 in Russia. It passes from Livonia by the lakes of Ilmen and the Waldai 

 Hills, and is extended over a vast region to the N.E., where it constitutes 

 a large portion of the shores of the White Sea. This system consists of 

 flagstone, clays, marls, cornstoncs, and sandstones, the whole bearing a 

 considerable resemblance to some red deposits of the same age in our 

 isles, but difTering by containing copious salt springs, and much gypsum. 

 It was the occurrence of so much salt and gypsum, that led previous 

 writers to consider these deposits an equivalent of our new red system, 

 which, being found to contain the same mineral in the western parts 

 of Europe, had been even termed by some, the saliferous sj^stem. 

 That the red deposits (red and green) are, however, the true equivalents 

 of our old red sandstone, is demonstrated, not only by order of superpo- 

 sition, but also by the many organic remains which they ofTer. Fishes 

 are the most distinguishing fossils of this great Russian system, and among 

 these are^pecies (notably the HoloptycMus nohilissimus, Murchison, with 

 the Coccosteus, Diplopterus, and Ctenoptychius of Agassiz), forms which 

 occur in deposits of the same age in Scotland. The fishes are in abund- 

 ance, and a work, illustrative of them, ^ is now preparing by Professor 

 Asmus, of Dorpat, near which University they abound. The authors 

 have traced these fisli-beds for a great distance, occupying several stages 

 in the system, and each stage characterized by peculiar species of ich- 

 thyolltes. 



The zoological contents of this system are also of great value in illus- 

 trating and confirming the palseozoic classification proposed by Messrs 

 Sedgwick, Murchison, and Lonsdale ; or, in other words, the evidences 

 found in Russia leave no doubt that the old red and Devonian systems 

 of rocks are identical. The Ortkis subfusiformis, O. striata, Spiri/er 

 cctlcarata, S. trapezoidalis , Prodtictus caperatus, Terehratula prisca (large 

 var.), and Serpula omphaloides, shells distinct from those of the carboni- 

 ferous system, but similar to those which occur in Devonshire, West- 

 phalia,. Belgium, and other places (in deposits which have been shewn by 

 these authors to be of the age of the old red sandstone), are found in 

 Russia in the same beds with the fossil /ishes of the old red sandstone of the 

 British Isles. 



Still more striking, observe the authors, are these cumulative proofs, 

 •when it is stated^ that although in France and Germany there are scarcely 



* See Silurian Researches^ p. 165, and Table with the Map. 



