94: Dr. Berger on the physical Structure 



nature of the rocks of a district, but likewise the general dispo- 

 sition of the strata, and their relation in point of position to the 

 surrounding country) one of the most interesting undoubtedly is 

 that of flint in chalk, which is subordinate to the secondary forma- 

 tion in the great and generally admitted division of rocks into primU 

 tive, transition, and secondary. 



Whatever be the country, where the formation of flint in chalk 

 or marl occurs, it is worthy of remark : 



I. That it occupies a considerable extent. 



II. That it belongs to flat countries stratiform or alluvial : and 

 what appears to me a more striking circumstance is, that as far as I 

 know, it is to be met with chiefly on the skirt of some great chain 

 of mountains at some distance ; as if it made one of the links of 

 a complete system of formations. Thus, in France, it prevails on 

 the skirt of the western boundary of Mount Jura, extending nearly 

 in a direction from S. E. to N. W. and covering a space of at least 

 two hundred and ten miles long, by about one hundred and fifty 

 broad.* In Poland, on the borders of the chain of the Carpathian 

 mountains, from the shores of the Baltic, comprehending the plains 

 of the Pilica, of the Bug, and of the Vistula, as far as the first 

 heights where these rivers have their source, f In England, to the east 

 of the mountainous part of Devonshire and Cornwall, and stretch- 

 ing across to the German ocean. This formation is also found in 

 Ireland, Saxony, Spain, Denmark, and Sweden j but I do not suf- 

 ficiently know in what particular situations, to enable me to notice 

 them in a less general manner. 



From the nearly exact correspondence of the meridians under 



* Journ. de Physique, Mars, 1807. 



+ Geologie des Montagaes de Tancienno Sarmatie (Polognc d'aujourdhui) 

 I'Abbe Staszie. Journ. de Physique, Aout, 1807. 



par M. 



