of Serpentine, Src. in the Apennines. 191 



in the enTirons of Bristol,* in Wales, at Altenlead [Allen- 

 heads] in Northumberland, &c. with those of Norway des- 

 cribed by M. von Bach, which are so well crystallised that 

 one would be inclined to refer them to the primitive class, 

 if the black limestones and aluminous slate, containing or- 

 ganic remains, did not form part of them. 



If the granular sandstones of Clausthal bear, at first sight, 

 some resemblance to certain sandstones of the Apennines, they 

 differ from them much more by the presence of felspathic 

 grains, to which they in part owe their granular structure^ 

 by numerous metallic and calcareous spathose veins which 

 traverse them ; and yet none of the sandstones or slates of 

 the Hartz are calcareous, nor the argillaceous schist of 

 Nagenthal near Altenau, nor the spangled yellowish argil- 

 laceous slate of Schalk near Schulenberg, which contains so 

 many remains of entrochi, nor that of Rammelsberg, finally 

 none of those in the Hartz which I have tried, eifervesce ; 

 all the sandstone rocks of the Apennines are, on the con- 

 trary, very effervescent. 



What I have said of the Hartz applies to the transition 

 formations of Saxony, which, from their aspect, perhaps dif- 

 fer still more than these from the calcareo-sandstones of the 

 Apennines. 



The sublamellar black limestones of the environs of 

 Namur, Mons,+ &c. which all geologists refer to the ancient 

 transition formation, have not any resemblance to the grey 

 compact limestones of the Apennines. 



The transition rocks which I have seen in France at 

 Montchatou near Coutances, and which sufiBciently resemble 



* The author is in error with regard to the Bristol limestone, which 

 is the medial or carboniferous limestone, and not the submedial or tran- 

 sition. The Northumberland is most probably the same ; as may also 

 the limestone the author mentions in Wales, at least if he means that 

 most abundant in South Wales: foreign geologists generally refer this 

 rock to the transition series, the limestone of which it certainly more 

 resembles than that of the secondary. [Translator.] 



+ This limestone is also analogous to our carboniferous or mountain 

 limestone. [Translator.] 



