398 Foreign Literature and Science. 



general, the level of the sea has actually undergone a slow 

 and progressive abasement, since the origin of things, the au- 

 thor undertakes to explain the manner in which the tertiary 

 deposits of the environs of Paris have been formed, and those 

 connected with them, both in the direction of the Loire, and 

 beyond the channel, to the neighborhood of the Isle of Wight. 

 The substance of his mode of explanation is this : First 

 epoch. A sea, calm and deep, deposits the two varieties of 

 chalk, which constitute the borders of the bottom of the great 

 tertiary basin we are speaking of. Second epoch. In con- 

 sequence of the progressive sinking of the ocean, the great 

 basin becomes a gulf, in which the flow of rivers forms 

 chalk, breccia and plastic clay, which are soon covered by 

 the marine spoils of the first calcaire grossier. Third epoch. 

 The deposits are interrupted by a commotion which breaks 

 and visibly displaces the beds. The basin becomes a salt 

 lake, traversed by voluminous currents, issuing alternately 

 from the sea and from the continents, and which present the 

 mixture and intermingling of substances which characterise 

 the second calcaire grossier, the calcaire siliceux, and the gyp- 

 sum. Fourth epoch. An irruption of a great quantity of 

 fresh water, charged with clay and marl, in the midst of which 

 there continued to form some deposits of bivalve marine 

 shells. The basin is no more than an immense pond of 

 brackish water. Fifth epoch. The basin ceases to com- 

 municate with the ocean, and the level of its waters sinks be- 

 low that of the sea. The muddy depositions of the continen- 

 tal waters continue. Sixth epoch. An accidental irrup- 

 tion of the ocean, which deposits sand and superior marine 

 grit; immediately after, the basin almost filled, contains only 

 fresh water, of little depth ; it receives a less influx from the 

 land vegetables, and lake animals begin to prevail, and mill 

 stone and fresh water calcaire are deposited. Seventh epoch. 

 The succession of these various operations is terminated by 

 the diluvian cataclysm." 



The academy directed that the work of Constant Prevost 

 should be printed in the Recueil des savans etrangers. — Idem. 



9. Nature of Brome. Electric Conductibility. — A letter 

 from Auguste De La Rive, professor of chemistry, of Ge- 

 neva, to M. Arago, dated Geneva, June 4, 1827, contains the 

 ' following interesting particulars. 



