1813.] 



On Formathns, 



201 



Cuvier is of opinion that the first two formations, viz. the chalk 

 and limestone, are of marine origin, because- they contain prin- 

 cipally sea shells; but the limestone contained also many fresh 

 water shells. The third formation, the gypsum, from its con» 

 taining remains of land quadrupeds, birds, and fresh water 

 shells, is conjectured to have been deposited from fresh water; 

 but it also contains marine shells. The fourth, or sandstone 

 formation, from its containing principally marine shells, is said 

 to be of marine origin. The fifth formation, from its containing 

 principally fresh water shells, is conjectured to have been depo- 

 sited from the water or a lake. The sixth, the alluvial formation, 

 has been formed in the same manner as other alluvial deposites. 

 According to Cuvier and Brongniart there appears to have been 

 an alternate appearance and disappearance of fresh and salt 

 water, an opinion which is not borne out by the facts stated in 

 the essay. The opinions of Braard, La Metherie, and others, in 

 regard to the kind of fluid from wliich these strata have been 

 deposited, like the hypotheses of the authors of tl;ie essay, are 

 sufficiently ingenious, but unsatisfactory. 



Having premised this short account of the formations around 

 Paris, we shall next notice some objections that have been started 

 against the Werneri&n geognosy, from the appearances presented 

 by these rocks. It has been said, The authors of the descrip- 

 tion of the country around Paris have themselves remarked that 

 the appearances exhibited in that country are not consistent with 

 the doctrines of the Wernerian schooL We must add, that to 

 us they appear most adverse to the theory of universal forma- 

 tions, the favourite and distinguishing dogma of that school. 

 Eleven formations are here enumerated, and shown to succeed 

 one another in one uniform order. They do so, however, only 

 over a certain tract ; and have none of them the least pretensions 

 to be reckoned universal." The authors of the essay have in no 

 part of it said that the appearances they describe are inconsistent 

 with the doctrines of the Wernerian school : on the contrary, it 

 is evident that they consider their descriptions as adding a new 

 set of rocks to that system, by means of which they have been 

 able to render their investigations so interesting. It is true that 

 a considerable series of formations succeed one another in one 

 uniform order ; but they are not confined to a small tract of 

 country; part of the sei-ies has already been traced tlirough 

 France to the confines of Switzerland, and by one of the authors 

 of the essay ; and we are informed by Dr. StelFens, that the 

 gypsum of Mont Martre occurs at Kiel in Holstein, on the 

 shores of the Baltic: and now that the attention of mineralogists 

 has been pailicularly directed to these rocks, we may expect to 

 hear^of their being found in other quarters of the globe. Even 

 allowing, for the sake of argument^ that this series of rocks liaJ 



