173 



North America, geologically coloured according to our 

 own classification, and described by the surveyors who 

 had constructed them after examining the countries, and 

 who described their embedded fossils as similar to our 

 own. Professor Rogers even exhibited a Crustacean* 

 from the Lower Silurian of North America — a well-known 

 North Wales species — as affording evidence of what he 

 termed " a very ancient sympathy between the two 

 countries." The analogy of genera and species over 

 such wide regions ia very remarkable, and unlike the 

 facts observed in the present day. The theory of the 

 universality of the most ancient Fauna may, however, be 

 modified, according to the observations of M. Barrande, 

 who seems to have discovered distinct zoological pro- 

 vinces in the Silurian strata of Bohemia. 



The records of the Flora and Fauna of foreign repre- 

 sentatives of British systems, do not differ essentially 

 from those recorded in our own strata. A compila- 

 tion of the organic classes peculiar to each successive 

 era, ■would differ very little from the one before you 

 representing the British strata. There is no occurrence 

 of Vertebrata in earlier strata than it is in England ; and 

 to the first examples of Fishes, Reptiles, Birds, and Mam- 

 malia, the main interest of the subject is attached. The 

 discovery of Chelonian Reptile tracks in the Lower 

 Silurian of North America requires confirmation. The 

 mammalian jaw, described by Dr. Emmons, from the 

 Permian strata of that country, is assigned to the Lower 

 Oolite by Sir Charles Lyell. It is probably the most 

 ancient example of mammalian remains yet discovered. 



Palasontology is a science in which new discoveries are 

 liable to alter its conclusions, in respect to the range of 

 organic remains through successive systems, and, there- 

 fore, any deductions arrived at, are simply the results of 



* Paradoxidcs Forcliliamnicii. 



