W6 On Formations, [MARCffy 



structure of the earth and its history? We learn nothing more 

 than what took place where the lake was situated. 



Even supposing the lake to have been of considerable extent, 

 still what took place within it could not afford us general lavi^s, 

 such as we obtain by considering the universal formations, as 

 clay slate, grey wacke, gneiss, mica siaie, Sec. 



The formation of iEningen, as Von Buch well remarks, 

 afFonds a most striking example of the necessity and importance 

 of distinguishing general from partial or /oco'/ formations. Had 

 naturalists known that the limestone slate of JKmngen was a 

 local formation, we should not have had so many erroneous 

 views and absurd inferences drawn from the petrifactions it 

 contains. 



Another set of formations, w^hich of late has excited much 

 attention, shall next be noticed. It is the series of new fioetz 

 rocks around Paris, and which is by some naturalists, although 

 probably incorrectly, conjectured to be a partial or local deposite. 

 When 1 first turned my attention to the descriptions of this tract 

 of country contained io t!ie Continental Journals, 1 was led \o 

 conclude that it differed from any of those contained in the 

 arrangement of Werner^ and stated it, as my opinion, that it 

 appeared to be of comparatively recent origin. This inference, 

 the truth of which has been demonstrated by the observations of 

 Cuvier and Brongniart, I was enabled to make by applying the 

 principles of the Wernerian geognosy to the accounts that had 

 been publislied. From these it apppeared that this tract of country 

 was composed of alternate beds of sand, clay, marl, earthy soft 

 limestone, sandstone, and gypsum ; in which were contained 

 numerous petrifactions of quadrupeds, birds, and other organic 

 remains. Now as Werner has ascertained that the older forma- 

 tions are compact and solid, the nev^er in general loose and 

 earthy; further, that remains of quadrupeds and birds occur 

 only in the newer formations; 1 concluded, from the looseness 

 of the texture of the Parisian strata, and their containing remains 

 of quadrupeds and birds, that very probably they belonged to a 

 new formation, or formations, more ancient than the oldest 

 alluvial deposite, but newer than chalk. 



It would appear from the late observations of Cuvier and 

 Brongniart in their " Essai sur La Geograpliie Mineralogique des 

 Environs de Paris,^* that the rocks of these formations are depo- 

 sited in a iiollow or bason of chalk, which forms the fundamental 

 rock, or immediate basis .of the district. These formations, 

 according to the French naturalists, are 1 1 in number, viz. : — 

 1. Chalk; 2. Plastic clay; 3. Coarse limestone; 4. Siliceous 

 limestone; 5. Gypsum, of the first fresh water formation; 

 6. Marine marl ; 7* Sand and sandstone, without shells ; 



Sandstone, of marine formation ; 9. Millstone, withou 



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