OF THE PARIS BASIN. 



2. MARLS OF MEUDON. 



These local marls, which are well developed at Meudon, are 

 occasionally very strontianiferous. They are white, unctuous, 

 and contain 20 per cent, of carbonate of strontian, 75 per cent. 

 of lime, and 5 per cent, of clay.* They are many yards in thick- 

 ness, and have been divided into two parts. (i) The lower, 

 containing hard nodules of limestone, apparently rolled, with 

 Potamides inophiatus and other mollusca, which M. de Lapparent 

 thinks f are derived from the destruction of a bed contempo- 

 raneous with the Cakaire de Mons ; and (2) the upper, having 

 concretions fissured with Viviparus aspersus, Rillyia rillyensis, Helix 

 hemisphdrica and other shells, the whole presenting much analogy 

 with the fauna of the Rilly beds presently to be described. Professor 

 Prestwich, F.R.S., states, X hesitatingly, that he should feel disposed 

 to refer all the lower Tertiaries of Meudon to a much higher 

 horizon, and to classify them with our Woolwich and Reading 

 series. 



3. SANDS OF BRACHEUX.§ 



As a general rule these sands repose directly on the Chalk. At 

 Bracheux, near Beauvais, they are about thirty-nine feet in thickness, 

 very glauconitic, and contain Ostrea bellovacensis, Ardica Scu- 

 tellaria, Cuculhea crassatina, Axincea terebratularis, Venericardia 

 pediincularis, Volutilithes depressus and other mollusca, the more 

 important of which have been given in a list by Prof. Prestwich. jj 

 Other fossiliferous localities exist near Beauvais, but the shells 

 require to be treated on the spot and carefully removed, as they 

 are very friable. We were informed that fossils could be obtained 

 at Abbecourt and Noailles ; but a visit to the last-mentioned place, 

 although showing a magnificent section well repaying the visit, 

 was disappointing from a pakxontological point of view. 



4. SANDS OF LA FERE AND CHALONS-SUR-VESLE. 



The sands of La Fere in the Aisne, which form another local bed 

 resting on the chalk, are composed of \ery fine sands with grains 

 of glauconite, and contain a small quantity of argillaceous or 

 calcareous matter. They have a total thickness of about twenty 

 feet. The glaucoiiie i?tferieure is a bed on this horizon, well 



* Jannettaz, Bull. Soc. Geol. Fr., 2''-. s6r., . xxix. (1S72), p. 41. 



t De Lapparent, Ttaitc dc Geol , 2 ed. (1885), p. 1127. 



+ Prestwich, Quart. Journ. Geol. Soc, vol. xliv. (1888), p. 90. 



§ In describing these sands at this stage we do not necessarily controvert the opinion of 

 those who have given reasons for placing them higher in the Tertiary series. This is not a 

 correlation paper, and we cannot, therefore, discuss the points at issue; the order here 

 adhered to is that adopted by the majority of French geologists. In any case the Sands of 

 Bracheux are of Lower Eocene age. 



|{ Prestwich, op. cit., pp. 96, 97. 



