1824.] Older Red Sandstone Formation, fyc. 17 



nature ; while in the construction of the term rothe todte lie- 

 gende, a double error is committed ; namely, a positive one, ia 

 applying it at all to the weissliegende (the calcareous, or new 

 conglomerate, the lowest bed of the alpine or magnesian lime 

 stone), an error sufficiently exposed by Freiesleben (vol. iii. p 

 239) ; and a negative one, in not applying it where alone it is 

 strictly due ; namely, to the red sandstone of the carboniferous 

 series in general. It follows that the rothe todte liegende and 

 porphyry of the Synoptical Table of Mr. De la Beche, are both 

 superfluous and out of place, the todte liegende being, as already 

 repeatedly observed, but an adjunctive designation of the red 

 sandstone of the carboniferous series, and porphyry occurring 

 both among the coal measures and in the old red sandstone. 



It will be seen from the memoir of M. de Bonnard, that the 

 carboniferous series of the Palatinate is also associated with 

 trap rocks, maintaining in this respect likewise its analogy to 

 the same series in other countries. 



The porphyry of Mont Tonnerre, &c. upon which this carbo- 

 niferous series reposes on its eastern confines, appears to be of 

 primary origin, containing veins of tin and other metals. Near 

 Alberschweiler the porphyry passes into granite. 



French geologists have generally, until very lately, been in 

 the habit of referring the carboniferous limestone and the old red 

 sandstone to the transition series, and hence the former has been 

 designated by them as transition limestone, and the latter as a 

 greywacke. The memoir of M. de Bonnard, and the map and 

 memoir of M. Omalius d'Halloy, are indicative of more correct 

 views. That their former persuasion may have been mainly 

 influenced by the declaration of M. von Humboldt, respecting 

 the English carboniferous limestone and old red sandstone, 

 appears very probable.* The opinion of this distinguished 

 naturalist respecting the Derbyshire limestone appears to have 

 been adopted at a very early period, before its relations had 

 been well ascertained ; and with respect to the old red sandstone 

 of Herefordshire, considered by him as transition or greywacke, 

 it has evidently been confounded with the real transition red 

 sandstone of that county. Indeed M. von Humboldt expressly 

 states (p. 107 and 159 of the Essai), that the transition red 

 sandstone of May Hill, the transition limestone of Longhope, 

 the old red sandstone of Mitchel Dean, and the mountain lime- 

 stone above it, are but repetitions or alternations of the seme 

 sandstone and limestone, all belonging to the transition series. 

 This is a view, however, that will not receive support from any 

 British treolosist ; and that the two latter formations are essen- 



• See the Traite de Gcogr.osie of M. d'Aubuisson, vol. ii. § V56 ; and the Essai sur 

 le Gisemcnt des Roches dans les deux Hemispheres, of the Baton Alexander von Hum- 

 boldt, passim. 



New Series, vol. v in. c 



