218 Parallelism of the Palceozoic Deposits 



Art. XX. — Parallelism of the Palceozoic Formations of North 

 America, with those of Europe ; by Ed. de Verneuil, trans- 

 lated, with annotations by James Hall. 



(Continued from p. 51.) 



M 



Europe 



j 





eral remarks upon the species of fossils common to the two coun- 

 tries, showing by a table of the successive groups the geological 

 range of the species. The first part of this we have translated 

 entire, while in the remainder we have noticed only those species 

 concerning which there exists some difference of opinion. 



We give in the following Table, the list of species common to Eu- 

 rope and North America. This list is made from our own obser- 

 vations, that is to say, we have seen in collections or in the rocks 

 the species which are here enumerated. We have placed oppo- 

 site to each species columns corresponding to the thirty-one groups 

 of which the palaeozoic formation in the United States is com- 

 posed, and we have indicated by asterisks those of the groups 

 where they are found. We can thus, by a simple inspection of 

 the table, easily understand the different duration of the species 

 and distinguish those which traverse many systems from those 

 which are limited to a single one. We can, moreover, which is 

 also essential, follow the succession of these last in the different 

 stages which compose that which is called a system. It will be 

 perceived that the species have very seldom lived throughout the 

 entire duration of the system of which they are said to be charac- 

 teristic ; that they have set out from different levels, and that 

 between the first and last beds, differences thence result, which 

 appear to prepare for the establishment of the succeeding system. 



The table contains one hundred and seventeen species, or about 

 one-fifth of all those which we have seen during our journey. 

 The four-fifths of the fossil species of the palaeozoic series of 

 North America appear, then, to be peculiar to this continent, 

 and thus prove to us that from the earliest times of creation, ani- 

 mals observed, in their geographical distribution, laws more or 

 less analogous to those which govern them at the present day. 



* This is very nearly the proport n which we have Already indicated in i our 



work upon Rt in. (Geologiede la Rustle d f Europe el lie lOural, vol. ii, p- 31.1 

 [In the first volume of the Paleontology of Ne w York, embracing descriptions « 



three hundred and eighty species of lower Silurian n . not more than one- twen- 

 tieth part can be regarded as identical with species heretofore described in Europe- 

 This number includes, however, some species known to occur !■ Europe, ou 

 -which have never been described, though it is not probable that the proportion o 

 species of this period common to the two continents will ever be found as great a 

 the proportion given by M. de Verneuil. In the upper Silurian and Devonian pe- 

 riod*, the proportion of species common to the two continents is probably greate 

 than in the lower stages.— J. H.] 



