Murchison on the Permian System, 27 1 



number of species collected by the authors in Russia is 53, or about 

 one- third of the total number of the whole European fauna of the 

 period, and of these 32 are peculiar to Russia, a large number when 

 the recency and rapidity of the survey of the authors is adverted to ; 

 and when it is considered that 33 species only were found by 

 Professor Sedgwick in deposits of this age in England, and 41, 

 according to the recent tabular view of Geinitx, is the total number 

 known in Saxony where the Zechstein is very fully elaborated. 

 Like other formations of synchronous age when at great distances 

 from each other, the Russian succession of Permian strata cannot 

 be brought into a detailed analogy with that of western Europe. 

 Instead of occupying a fixed place like the calcareous beds which 

 represent the Zechstein, they inosculate with great thicknesses of 

 fossiliferous grit, whilst Saurians and fishes with certain Producti 

 and Modioli, as well as most of the plants, unquestionably occur in 

 conglomerates, tufaceous limestone, and marls, which overlie the 

 beds which contain Zechstein or Magnesian limestone fossils. In 

 Germany, the Protorosaurus belongs to the Cupfer-schiefer which is 

 below the Zechstein, whereas in Russia all the cupriferous and 

 sauroid beds are above that rock. 



In analysing the species common to the Permian system of 

 Russia and the rest of Europe (by stating the number which have 

 lived on from the carboniferous to the Permian, and the diminished 

 proportion of the latter), Russia alone is appealed to, and three only 

 of the Permian species of that country are found to descend into 

 the Palceozoic rocks. The authors, therefore, infer that these results 

 necessarily prove the existence of a relation between the greater or 

 less duration of species and their propagation or extension to distant 

 parts, thus confirming a law previously announced by one of them. 



Some detailed observations then follow on the species in each 

 class found in Russia, and Mr. Lonsdale is cited as having assured 

 them that although the Permian corals are evidently Palaeozoic in 

 their generic characters, there is not a single species which is identical 

 with a carboniferous form ; and it is also remarked that of 20 species 

 of Brachiopods found in Russia, 8 are peculiar to that country. 



Lastly, deriving their knowledge of the specific character of the 

 plants from the examination of M. Adolphe Brogniart, aided by Mr. 



2 N 



