216 Rev. W.D. Conybeare on a Geological Map of [March, 



beneath the lias along their northern and north-western escarp- 

 ment the saliferous sandstone (Lons le saulnier, &c). 



Dr.Boue has traced the variegated sandstone, alpine limestone, 

 and rotheliegende, skirting the Vosgeson the left bank of the 

 Rhine, where the continuation of this tract approaches the slate 

 mountains of the Ardennes. It has been described by Omalius 

 d'Halloy, who classes this series agreeably to its disposition in 

 England as the oldest of the horizontal rocks, contrasting it 

 with the inclined position of the coal and older formations. 



Keferstein states, that the primitive range of the Schwartz- 

 wald and Odenwald on the right bank of the Rhine is succeeded 

 on the east, first by rothetodte, then by alpine limestone, and 

 thirdly by variegated sandstone; and according to his repre- 

 sentation, the Wurtzburg calcareous platform is a portion of 

 this band of alpine limestone. Boue and Humboldt, however, 

 I believe, consider the same tract as muschel kalkstein. Having 

 hastily traversed it myself, I felt also inclined to embrace the 

 latter opinion. 



Between this limestone and the cavernous (Jura) limestone of 

 Bamberg, a tract of conglomerate and sandstone intervenes. 

 Keferstein refers this to the variegated sandstone forming the 

 third zone, consistently with his general ideas of the structure of 

 this district; but if the Wurtzburg tract be muschel kalk, this 

 sandstone district is, perhaps, equivalent with the sand of our 

 inferior oolite. I felt much embarrassed by this district when I 

 traversed it, and have not yet been able to procure information 

 which fully satisfies me.* 



After passing the platform of Jura limestone between Bamberg 

 and Bayreuth, however, the red marl of the variegated sandstone 

 is unequivocally displayed resting against the Bohemian chains, 

 the Fichtelgebirge, and the Thuringerwald. 



(G.) North of Germany. 



In the point to which we have now arrived, we may observe 

 skirting the Thuringerwald all the formations noticed at the head 

 of this article, viz. the red marl and gypsum ; the calcareous 

 beds associated with the cupriferous marl slate, and at the bot- 

 tom the rothetodte : a shell limestone answering to our lias rests 

 on these beds, and separates this from a similar district encir- 

 cling the detached ancient group of the Hartz mountains : here, 

 and in the continuation of this district towards Halle, the rothe- 

 todte is to be observed in many places in contact with the coal 

 formation, and always above it. Rock salt is found in numerous 

 points in this quarter, along the line between Osnaburg and 



* I have, therefore, followed the authority of Keferstein in colouring my map, prefer- 

 ring to copy the errors, if errors they be, of the best published document, rather than sub- 

 stitute an original representation from very imperfect observations, which would, 

 therefore, have been quite as likely to prove erroneous. 



