CHAPTER XVII. 



Eocene period Fresh-water formations Central France Map Limaghe 

 d'Auvergne Sandstone and conglomerate Tertiary Red marl and sandstone 

 like the secondary ' new red sandstone' Green and white foliated marls 

 Indusial limestone Gypseous marls General arrangement and origin of the 

 Travertin Fresh-water formation of the Limagne Puy en Velay Analogy of 

 the strata to those of Auvergne Cantal Resemblance of Aurillac limestone 

 and its flints to our upper chalk Proofs of the gradual deposition of marl 

 Concluding Remarks. 



EOCENE FRESH-WATER FORMATIONS. 



WE have now traced back the history of the European for- 

 mations to that period when the seas and lakes were inhabited 

 by a few only of the existing species of testacea, a period 

 which we have designated Eocene, as indicating the dawn of the 

 present state of the animate creation. But although a small 

 number only of the living species of animals were then in being, 

 there are ample grounds for inferring that all the great classes 

 of the animal kingdom, such as they now exist, were then fully 

 represented. In regard to the testacea, indeed, it is no longer 

 a matter of inference, for 1400 species of this class have been 

 obtained from that small number of detached Eocene deposits 

 which have hitherto been examined in Europe. 



The celebrated Paris basin, the position of which was 

 pointed out in the former part of this volume, (see wood-cut, 

 p. 16) first presents itself, and seems to claim our chief 

 attention when we treat of the phenomena of this era. But 

 in order more easily to explain to the student the peculiar 

 nature and origin of that group, it will be desirable, first, to 

 give a brief sketch of certain deposits of Central France, which 

 afford many interesting points of analogy, both in organic 

 remains and mineral composition, and where the original cir- 

 cumstances under which the strata were accumulated may 

 more easily be discerned. 



VOL, III. Q 



