20 ORIGIN OF THE EUROPEAN TERTIARY [Ch. II. 



strata*, placed the crag as the uppermost of the British series, 

 and several geologists began soon to entertain an opinion that 

 this newest of our tertiary formations might correspond in age 

 to the Italian strata described by Brocchi. 



Tertiary Strata of Touraine. The next step towards esta- 

 blishing a succession of tertiary periods was the evidence 

 adduced to prove that certain formations, more recent than 

 the uppermost members of the Parisian series, were also older 

 than the Subapennine beds, so that they constituted deposits 

 of an age intermediate between the two types above alluded 

 to. M. Desnoyers, for example, ascertained that a group of 

 marine strata in Touraine, in the basin of the Loire (e, dia- 

 gram No. 3), rest upon the uppermost subdivision of the 



No. 3. 



Tourainq 



C, Chalk and other secondary formations. 



d, Tertiary formation of Paris basin. 



e, Superimposed marine tertiary beds of the Loire. 



Parisian group d, which consists of a lacustrine formation, ex- 

 tending continuously throughout a platform which intervenes 

 between the basin of the Seine and that of the Loire. These 

 overlying marine strata, M. Desnoyers assimilated to the En- 

 glish crag, to which they bear some analogy, although their or- 

 ganic remains differ considerably, as will be afterwards shown. 

 A large tertiary deposit had already been observed in the 

 south-west of France, around Bordeaux and Dax, and a de- 

 scription of its fossils had been published by M. de Basterotf . 

 Many of the species 'were peculiar, and differed from those of 

 the strata now called Subapennine ; yet these same peculiar 

 and characteristic fossils reappeared in Piedmont, in a series of 



* Outlines of the Geology of England and Wales, 1 822. 

 f Mem. de la Soc. d'Hist, Nat. de Paris, tome ii-, 1825. 



