M. Barrande on the Silurian System of Bohemia. 121 



common with England, and hence the seas then were pro- 

 bably more isolated. In Sweden no formations higher than 

 those of Gothland occur. It is curious that whilst the Lower 

 Silurians of France shew no analogy with the lower lime- 

 stone of Bohemia, it is in that country that the gi'eatest 

 number of species identical with the middle limestone stage 

 F have been found. Vire in the Sarthe Dept has furnished 

 already eight species. 



In North America no identical species have been noted 

 from the lower rocks, but from the upper division 21 species 

 are found in M. de Verneuil's lists. Almost all of these are 

 from the Clinton and Niagara groups ; and further examina- 

 tion will probably shew more numerous identities. 



The countries nearest to Bohemia on the continent are 

 still so little known as to permit only of a very imperfect 

 comparison. In the Fichtelgebirge he seems to regard the 

 Orthoceratite and Clymenia limestones as approximating to 

 his stage E ; the first deposit being probably the lower and 

 Silurian, the second higher and Devonian. The Thuringer 

 Wald and Saxony contain ancient rocks, but the materials of 

 comparison are still wanting. 



This notice of a few of the more general results which M. 

 Barrande has deduced from his study of the ancient rocks of 

 Bohemia will, we trust, induce some of our readers to look 

 into the work itself, and to encourage the author — an exile 

 in a distant land — to proceed in his researches, by promoting 

 the sale of his book. The account of the classification, 

 development, and geological distribution of the Trilobites is 

 singularly interesting, the abundance of materials which he 

 has collected, with great labour and expense, having enabled 

 him to add many new facts to the history of this long extinct 

 race of animals. As the Silurian formations formed the 

 centre of their development in time, so Bohemia might be 

 supposed the centre of their geographical distribution, did 

 not facts which we have recently seen prove that parts of 

 our own land are perhaps no less rich in these curious 

 Crustaceans, were they only sought with equal diligence. In 

 regard to the other tribes, his work will, we expect, furnish 

 materials scarcely less valuable to the student of the ancient 

 rocks. 



