ao2 



On Formations, 



[March, 



Bot been traced further than the gates of Versailles, I ask, should 

 we be entitled from thence to conclude, from the mere extent of 

 the mass, that it would not on examination prove to be an 

 universal formation ? 1 apprehend we could not, for this reason, 

 that many of the formations now acknowledged to be universal 

 were at first observed extending over very inconsiderable tracts of 

 country. But the formations might be local ones, and therefore 

 would not extend far ; and yet such an appearance, instead of 

 militating against this doctrine of the Wernerian school, would 

 be an illustration of the truth of it. 



it has further been remarked " that this same survey of the 

 country around Paris is equally adverse to another doctrine of the 

 school of Freyberg, closely connected with the former. The 

 mineralogists of that school, it is said, have boldly ventured to 

 assign to every stratum its individual place; and to fix, with more 

 than prophetic skill, the order in which the different formations 

 of the mineral kingdom will be found to succeed one another 

 over the globe. If these pretensions are well founded, nothing 

 in the science of mineralogy can be so valuable as the knowledge 

 they must confer : if they are ill founded, nothing can be more 

 pernicious than the errors into which they will betray. Every 

 thing, therefore, is of importance, that brings them to the test of 

 experience. Novv^ it is remarked by Brongniart, that the order 

 laid down by Werner is inverted in the case of the chalk. That 

 substance is made the fifth of the floetz formation, and is placed 

 above the highest floetz gypsum. Here, however, it appears far 

 below it, vi'ith several formations between. The rule of Werner, 

 therefore, does not hold in this instance ; and it has been proved, 

 that though the gypsum of Mont Maitre agrees pretty nearly in its 

 minerai cliaracters with th^ newest gypsum formation of Werner, 

 it differs entirely in its geological position. Again: the chalk 

 described in this e:;say is not only covered by gypsum, but by 

 limestone, and the gypsum by a second stratum of limestone and 

 of sandstone, besides the siliceous millstone ; all which is quite 

 inconsistent with the Wernerian arrangement. All this shows 

 how very imperfect that arrangement is, notwithstanding its pre- 

 tended iofallihility." If the limestone and gypsum of this series 

 of rocks had been precisely the same with the second floetz 

 limestone, and the second floetz gypsum, then there might have 

 been a shadow of plausibility in the remarks just stated; but the 

 preceding descriptions demonstrate that they differ most com- 

 pletely from these formations, not only in their eryctognostic, 

 but also in their geognostic relations. Brongniart, indeed, was 

 so convinced of the truth of this, that far from viewing them as 

 proofs of the fallacy of tlie geognosy, he describes both the 

 iiraestone and gypsum as new and distinct formations : the'' one 

 he names coarse limestone, to distinguish it from the older floetz 



