THE EOCENE BEDS 



CLASSIFICATION OF THE PARIS BASIN EOCENE. 



( f. Ligurian 13. Gypsum and marls. 



r) • . r> ^ ■ I !-• Limestone of St. Ouen. 



Parisian ... , e. Bartonian ... < , <-. , , ,, 



I III. babies Moyens. 



\d. Lutetian 10. Calcaire Grossier. 



( c. Ypresian ... 9. Sands of the Soissonnais. 



I i 8. Sands of Sinceny. 



b. Sparnacian . . < 7. Lignites of the Soissonnais, &c. 



Suessionian.-; ( 6. Plastic clay. 



r 5. Rilly limestone. 



I 4. Sands of La Ffere and ChalonE-sur-\^esle. 



ya. Maudunian.. -' 3. Sands of Bracheux. 



I 2. Marls of Meudon. 



l^ I. Pisolitic limestone. 



The word Suessionian {Suessome?i of d'Orbigny) is derived 

 from the Latin name of Soissons — Suessiones ; Maudunian from 

 Meudon ; Sparnacian from Sparnacum, Epernay ; Ypresian from 

 Ypres (Belgium) ; Lutetian from Lutetia, Paris ; Bartonian from 

 Barton (Hants) ; Ligurian from a district of north-west Italy. 



1. PISOLITIC LIMESTONE. 



At Meudon, near Paris, this bed is seen resting on the Chalk ; 

 typically it is a yellow limestone composed of small rounded 

 grains and largely made up of pieces of shells. The same bed 

 has also been found, amongst other places, at Bougival, Vigny, 

 Laversine, Ambleville, Montainville, Flins, Montereau, La Faloise, 

 and Mont-Aime near Yertus. Its thickness varies from 6 feet 

 6 inches at Meudon to 162 feet at Mont-Aime, and, following 

 the different localities, the lithological character somewhat 

 changes. The following fossils of this horizon may be cited as 

 characteristic : — Nmitilus daiiicus, JV. Heberti, TrocJms Gadrie/i, 

 some large Cerithia, Crassatella pisolithica, Corbis vinltila)nel- 

 losa, Cardium^ Lima, Ostrea and Cidaris Forchhammeri (C. 

 Toinbecki). A glance at this fauna at once shows that the 

 Pisolitic Limestone is a passage bed between the Secondary and 

 Tertiary formations ; hence, like other similarly-situated beds in 

 Belgium and elsewhere, it has suffered many vicissitudes— at one 

 time being classed with the former, and at another with 

 the latter. But the incontestable affinities of the major part of 

 the fossils with those of the Calcaire de Mons, in the south of 

 Belgium, lead us to follow those who include the " Calcaire 

 pisolithigiie" in the Tertiary; we are nevertheless of opinion 

 that it is older than the Belgian bed referred to. It seems 

 to occupy a position intermediate between the Calcaire de 

 Mons and the Jnfeaii de Ciply, and as such should be classed 

 with the Palaeeocene series of continental geologists. For the 

 sake of clearness, however, we have not included the fossils found 

 in this bed in the accompanying list of moUusca (p. 64). 



