18 Mr. Weaver on the [July, 



tially distinct from the two former, will, I trust, be made suffi- 

 ciently evident in a paper of mine, which will appear in the con- 

 cluding part of the first volume (New Series) of the Geological 

 Transactions, now in course of publication. That the opinion 

 of M. von Humboldt is altogether founded in misconception, 

 particularly of the language of Prof. Buckland, must, I think, 

 clearly appear from the following extracts : — 



" The old red sandstone of Herefordshire of Mr. Buckland, 

 placed below the transition limestone (mountain limestone) of 

 Derbyshire, is a transition sandstone, as has been very well 

 indicated by this excellent geognost himself, in his Memoir on 

 the Structure of the Alps"* (Annals of Philosophy, June, 1821); 

 in which Prof. Buckland is made to say directly the reverse of 

 what he intended to express ; namely, that some foreign geolo- 

 gists (especially of the French school) had erroneously denomi- 

 nated as greywacke and transition limestone the old red sand- 

 stone and carboniferous limestone of the English, which, on the 

 contrary, are but the leading members of a totally different series ; 

 namely, of the carboniferous, or, in other words, of the grande 

 formation de gres rovge. Had M. von Humboldt himself had an 

 opportunity of studying the relative position, characters, and 

 freedom from fossil shells, of the old red sandstone of the British 

 Isles, it is impossible that he could have avoided recognizing it 

 as representing neither more nor less than the fundamental por- 

 tion of the carboniferous tracts. His own language indeed may 

 be adduced to prove this, being directly at issue with his former 

 position : " the red sandstone formation (meaning the carboni- 

 ferous series, see Dr. Boue sur l'Ecosse, p. 376), which occupies 

 the greater portion of Ireland, is common in the north of Ger- 

 many, in the Black Forest, and in the Vosges."+ Now these 

 tracts all belong to precisely the same series as the correspond- 

 ing tracts of Great Britain, and the old red sandstone of the one 

 has just as much pretension to a transition character, or the 

 name of greywacke, as the other. I may on this occasion advert 

 to the extremely loose manner in which the term greywacke is 

 employed by many German geologists, who are apt to include 

 sandstone in this designation, when found in the transition 

 period, and, as it appears (though unintentionally), when found 

 out of it, e. g. in the old red sandstone. If we are to speak a 

 language that shall always be intelligible, it becomes necessary 

 that each term should retain its own peculiar signification. A 



* P. 157 of the Essai. " Le vieux gres rouge (old red sandstone du Herefordshire) 

 de M. Buckland, place sous le calcaire de transition (mountain limestone) de Derby- 

 shire, est un gres du terrain intermediaire, comme cet excellent geognoste l'a tres-bien 

 indique lui-meme dans son Memoire sur la Structure des Alpes." 



-f- P. 212. " La formation de gres rouge qui constitue la majeure partie de l'lrlande, 

 et qui est si commune dans l'Allemagne septentrionale, dans la Foret-noire et dans les 

 Vosges, manque (de meme que la formation des porphyres) presque entierement dans 

 la* hautes Alpes de la Suisse." 



