IN THE PARIS BASIN. 



47 



chiefly found in the " First Mass " of Gypsum, and the white 

 marls associated with it. This is now built over. 



Argenteuil and neighbourhood can be reached from St. 

 Lazare, and several good quarries are worked in the Gypsum, a 

 little to the north of Argenteuil, on the roads to Sannois and 

 Enghien. A very fine section is that called Carriere Bast, at 

 Orgemont (see p. 32). The downward continuation of the beds 

 can be seen in another quarry nearer the railway. 



Beauchamp. — From Paris, Gare du Nord, to St. Leu. The 

 fossiliferous sections in the Middle Sables Moyens (Horizon of 

 Beauchamp) are within two miles of the station. 



Auvers, Mery,and Valmondois. — From Paris (Garedu Nord) 

 take train to i\uvers. The typical section is about one and a-half 

 miles due northof Auvers, on the top of the hill, passing the church. 

 That at Valmondois is within two miles of, and contains very similar 

 fossils to that at, Auvers. The important section, cut by the 

 railway at Mery, is well described by MM. G. Dollfus and G 

 Vasseur in the paper already referred to.* 



Vaugirard, Issy, and Meudon.— The farthest point, Meu- 

 don, can be reached from Paris via the Gare Montparnassc, and 

 the other sections are within walking distance. 



The following sketch section f will readily explain the relation 

 of the beds is this neighbourhood. 



Fig- I3-- 

 VaticxrcLrd 



■Section from Vaugirard to Meudon. 



r. ] I 1 I I I I 1 I. i.T-T 



6. Calc:iire Grossier. 4. Plastic Cla}'. 2. Pisolitic Limestone. 



5. Faussis Glaises. 3. Wiiite Marls. i. Chalk. 



IssY. — The Plastic Clay section at Issy is very near the fortifi- 

 cations, on the south side of the road from Vaugirard to Issy. 

 About one and a-half miles on the road past Issy, and close to the 

 west side of the Fort of Issy, is an interesting quarry in Upper 

 and Middle Calcaire Grossier. 



Meudon. — Close to the railway, about half-a-mile north of 

 Meudon, the Plastic Clay is again seen, together with the con- 

 glomerate formed of the debris of Chalk, Pisolitic Limestone, (S:c., 

 containing Gasfornis, Coryphodon, &c. On the south side of the 

 road from Issy to Meudon, near Bas Meudon, the Lower Calcaire 

 Grossier, the Plastic Clay, and the Pisolitic Limestone are again 

 seen ; the last mentioned resting unconformably on the Chalk. 



* Dollfus and Vasseur, Bull. Sac. GcoL de France. 3e. s^r., vol. vi. 

 t From Dr. Hovelacque's notes. 



p. 243, &c 



