1823.] the principal Mountain Chains of Europe. 211 



between this and the following deposits, and to introduce, as it 



were, the latter. 



6. The A/pine Limestone ; Zec/islein, or Magnesian Limestone. 

 {Werner's Jirst Floetz Limestone.)— This formation is very- 

 variable in different places, and may be said generally to present 

 in distant districts a parallelism rather than identity of deposits. 

 The prevailing rock in the continental deposits (zechstein) is a 

 2,rey compact, and generally argillaceous limestone ; sometimes 

 slightly granular, and having a small degree of lustre from the 

 facettes of the calcareous crystals imbedded : its colour is grey 

 or bluish, sometimes acquiring a reddish tinge ; it contains sub- 

 ordinate beds of magnesian limestone, of ferriferous limestone, of 

 cellular and crystalline limestone (rauchwacke), of fetid limestone, 

 and of bituminous and cupriferous marl slate. Copper, galena, 

 calamine, and mercury, are among the metallic products of this 

 formation ; and the association of rock salt and gypsum attest 

 its connexion with the superimposed sandstones which also 

 abound in these minerals. 



Organic remains are scarce in this formation, speaking gene- 

 rally,°but yet in particular spots and beds occur even abundantly : 

 the following species are enumerated by Sclottheim ; but I am 

 not at present able to identify all the names employed with the 

 synonymes in English writers. 



Gryphites aculeatus, 



G. gigas, 



G. arcuatus, 



Pecten textorius, 



Pecten salinarius, 



Mytilus rostratus, 



Terebratula alata, 



Terebratula lacunosa, 



tinguishing the rothetodte from the old red sandstone." I hope hereafter to communi- 

 cate from these letters a sketch of the recent discoveries of this active and persevering 

 geologist ; and here then for the present, at least, I shall close this controversy. I had 

 originally intended to have given more minute extracts from the original works referred 

 to ; but unless the accuracy of the general statements above given shall be questioned, it 

 will, perhaps, be superfluous to do so ; if they should be controverted, I am then pre- 

 pared to support them. En resume against the proposed identification of the rothe- 

 todteliegende and our oldest sandstone. I have the express testimony of Buddand, 

 Humboldt, Boue, Daubuisson, and Beudant, and (as I contend) the implied evidence of 

 every other writer on the subject, excepting, perhaps, of Prof. Jamieson. Whether it 

 be more properly referable to the upper part of the carboniferous, or the lower part ot 

 the saliferous series, is a distinct question, on which much division of opinion exists, and 

 which is after all not very material. I have endeavoured to compromise matters by 

 treating it as an intermediate link between them. 



I have thus endeavoured to support, as I may, the opinions which to me appear most 

 probable against an adversary from whom, however, I can never dissent without hesita- 

 tion. Mr. Weaver's memoir on the South-east of Ireland will long remain as one of 

 the most perfect models of geological description, and must excite our regret that we 

 have not been favoured with more original communications from the same pen ; while 

 his extracts from the writings of continental geologists, published in the Annnh, equally 

 attest Inn power of generalising, and presenting under their most luminous point of view, 

 the observations of others. 



p2 



