OF THE PARIS BASIN. 1 3 



This section is the downward extension of the Calcaire 

 Grossier seen at Le Vivray, the coarse-grained glauconitic bed 

 being exposed at the base of that section. 



At various levels in the sands of the Soissonnais concretions 

 of a peculiar character are met with, and, from their striking 

 resemblance to the head of a cat, are known as tetes de chat. 

 They are masses of tubercular calcareous sandstone or dolomitic 

 limestone, occasionally siliceous. The fossils of these sands are 

 almost innumerable ; but we may mention a few of the most 

 distinctive forms. The Foraminifera are especially abundant, 

 Niiiiunulites planulatus being met with in millions. Among 

 the Mollusca, the following are characteristic and plentiful :— 

 Melanopsis Farkinsani, Nerita tricarinata, Velates Schmide/i, V. 

 equitius, Diastoma variculosum, Brachytrema dreviailum, Potamides 

 subacntus, P. papalis, Homalaxis laudunetisis and Corbicula 

 GravesL The Vertebrata are represented by over thirty 

 species of fishes, according to Graves * and Paul Gervais.t 

 A long list of plants is given by Watelet % ^s composing the 

 flora of the sands of the Soissonnais. 



10. CALCAIRE GROSSIER. 



The Calcaire Grossier is a thick mass of more or less calcareous 

 beds, usually coarse in texture, varying from a calcareous sand to 

 a hard, compact limestone, sometimes dolomitic and siliceous. 

 The limits of this series of beds in the Paris basin have been well 

 described by M. G. Dollfus.§ The Lower or Marine Calcaire 

 Grossier has a more extended range northwards than the Fluvio- 

 Marine or Upper Calcaire Grossier. The former beds stretch 

 from Courtagnon and Damery on the east, and sweep round by 

 Montmirail to the south of Paris, by Villeneuve St. Georges, 

 Palaiseau, and Houdan. Towards Evreux and Dreux the bound- 

 ary is not very distinct, several tongues projecting from the main 

 mass. On the north and north-west again, no definite boundary 

 can be drawn, but the isolated patches over those parts of the basin 

 are traceable, with more or less certainty, into Belgium, and 

 are represented in England by rocks of similar age. 



The Fluvio-Marine type of the Calcaire Grossier is much more 

 restricted in extent, being unknown outside the limits of the Paris 

 basin. The former existence of two great lakes has been indicated 

 by M. G. Dollfus. || One of them stretched from the north of Epernay 

 to Montereau (a distance of at least seventy-five miles), bounded 



* Graves, Essai sur la Topographic Gcol. dc tOisc, p. 5S6. 



t Gervais, Zool. et PaUont. franfaises. 



% Watelet, Desc. des plantes/oss. dit Bass, de Paris (1866), p. 255. 



§ Dollfus, Essai sur t extension des Terr. Tcrt., etc., in Mem. dc la Soc. Gcol, dc 

 Normandie. Havre (1880), p. 591. 



II Dollfus, op. cit., p. 9, and map. 



