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Neiv Diluvian Formation of the Vosges. 



M. De Billy read a memoir on an argillaceous diluvian 

 formation observed in the department of Vosges. 



The author distinguishes four classes of diluvian formations 

 in the department of Yosges, namely,— 



1. The granitic diluvium, composed of pebbles and sands 

 produced by the disintegration of granites, gneiss, porphyries, 

 and other ancient rocks. 2. A deposit, composed of the 

 debris of Vosgian sandstone in the state of sand, quartzy 

 pebbles, angular fragments, and blocks of this secondary 

 sandstone. 3. An argillo-sandy diluvium, very frequently 

 filled ^vith rounded quartzy pebbles. 4. Argillaceous deposits 

 formed in the middle of Jurassic formation, and mixed with 

 a greater or less abundance of fragments of secondary 

 limestones. 



The work which M. De Billy communicated to the Society 

 is devoted to the third class of diluvium. 



This deposit is principally composed of an argillaceous 

 earth, sometimes sandy, more frequently plastic ; the colour 

 varying from light-grey to greyish-yellow, and to yellowish- 

 grey inclining to red. We generally find in it that kind of 

 quartzy pebbles everywhere so abundant in the Vosgian 

 sandstone. It sometimes happens, however, that the clay is 

 quite free from them. The localities where this argillaceous 

 diluvium has been observed are along the numerous water 

 courses which furrow the northern region of the depart- 

 ment of Vosges. It is noticed sometimes at the level of the 

 px'e!3ent waters, and even below them, sometimes a little 

 above ; and lastly, and this case is frequent, covering the 

 plateaux which overhang the valleys, and in which the 

 waters may be supposed to have deposited them when they 

 were of larger size, and ran at a higher level than in our 

 days. These currents of water, beginning at the east, are 

 tlie Mortagne Arentelle, Durhion, Moselle, and the Aviere. 

 The tliickness of the deposit, wliich frequently varies between 

 20 and 50 metres, reaches a height of 124 metres on the 

 banks of the Moselle, as in the neighbourhood of Charmcs. 



