UPPER MARINE SANDSTONE AND SAND. 



SEVENTH FORMATION. 



Of Sandstone and Sand zcithout Shells. 

 The sandstone with shells is one of the latest forma- 

 tions. It always rests on those already described, and in 

 general is only covered with the millstone without shells, 

 and the upper fresh water formation.* Its strata are 

 often of considerable thickness, are intermixed with beds 

 of sand of the same nature, and both are often so fine 

 that they are used in manufactories. 



EIGHTH FORMATION. 

 Marine Origin. 



Upper Marine Sandstone and Sand. 

 This sandstone^ or last marine formation, rests on the 

 gypsum, marine maft^TETiTl PHjtt.upon.the sandstone and 



sand without shells. It varies in colour, compactness, 

 and even in composition. Sometimes it is a pure sand- 

 stone, but friable, and of a red colour, as at Montmartre : 

 sometimes it is a red coloured clayey sandstone, as at 

 Romainville ; sometimes it is a grayish sandstone, as at 

 Levignan ; lastly, its place is occasionally occupied with 

 a thin bed of calcarious sand filled with shells, which 

 covers the great masses of gray, hard sandstone, and 

 without shells, at Nanteiulle-Haudouin. 



This sandstone contains marine shells, which are some- 

 times different from those found in the sandstone of the 

 lower marine formation, and approach more to the spe- 

 cies met with in the calcarious marl, which surmounts 



* It appears, as we shall afterwards show, that 'it is in some places 

 covered by a formation of marine sandstone or limestone. 



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