276 EOCENE PERIOD. [Ch. XX. 



Basin of the Cotcntin, or Valocjnes. The strata in tlie 

 environs of ValogneSj in the department of La Blanche, consist 

 chiefly of a coarse limestone resembling the calcaire grossier of 

 Paris; of which M. Dcsnovers has given an elaborate descrip- 

 tion. It is occasionally covered with a compact fresh-water 

 limestone alternating with fresh-water marls. In these Eocene 

 strata more than 300 species of fossil shells have been disco- 

 vered, almost all identical with species of the Paris basin. (See 

 Tables, Appendix I.) Superimposed upon the Eocene strata 

 of this basin is a newer marine deposit, extending over a 

 limited area, the fossils of which agree with those of the Faluns 

 of the Loire*. Here, therefore, the geologist has an opportu- 

 nity of observing the superposition of the Miocene deposits 

 upon those of the r.ge of the Paris basin. 



Rennet. Several small patches, also, of marine strata, have 

 been found by M. Desnoyers, in the neighbourhood of Rennes, 

 which are characterised by Eocene fossils and repose on ancient 

 rocks, as will be seen in the map. 



'Baai n of Belgium, or the Netherlands. The greater part of 

 the tertiary formations of the Low Countries consist of clay 

 and sand, much resembling those of the basin of London, after- 

 wards to be described. The fossil shells, also, arc of the same 

 species, 4-0 of which will be found referred to by M. Deshayes, 

 in the tables, Appendix I. 



Air, in Proicnce. The tertiary strata of Aix and Euveau 

 in Provence are of great thickness and extent, the lower mem- 

 bers being remarkable for containing coal grit and beds of 

 compact limestone, such as we only find in England in 

 ancient secondary groups. Yet these strata are for the most 

 part of fresh-water origin, and contain several species of Eocene 

 shells, together with many which are peculiar to this basin. It 

 would require a fuller comparison than has yet been made of 

 the fossil remains of Aix and Euveau, before we can determine 

 with accuracy the relative age of that formation. Some of the 

 plants seem to agree with those of the Paris basin, while many 

 * DesnoycrSj Mem. cle lu Sue. d'llibt. Nut. du Paris, 1825. 



