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



Article XL 



Memoir illustrative of a general Geological Map of the principal 

 Mountain Chains of Europe. By the Rev. W. D. Conybeare, 

 FRS.&c. 



(Continued from p. 1 49.) 



Great Saliferous Series, 



Including, a. The rothetodteliegende. 



b. The alpine or magnesian limestone. 



c. The variegated or new red sandstone. 



In comparing the series of deposits which immediately succeed 

 the great carboniferous order as presented in England, and in 

 some parts of the Continent, we shall, perhaps, perceive rather a 

 parallelism than identity of formations in the representatives of 

 rothetodteliegende and the alpine limestone ; but in the varie- 

 gated sandstone an unequivocal identity is manifested. 



a. Rothetodteliegende. — Conglomerates, including rolled frag- 

 ments of the neighbouring rocks, characterise this formation : 

 the cement is sometimes argillaceous, sometimes quartzose ; by 

 the diminution in size of the fragments, the rock often passes 

 into a sandstone more or less granular. Beds of red micaceous 

 shale alternate in the formation; it contains subordinately in 

 some places carboniferous beds (distinct, however, according to 

 Freisleben, from those of the true coal formation). Trap rocks 

 (amygdaloid and porphyry) are often associated with these 

 deposits, usually, as it should appear, in their lowest members 

 where they rest on the true coal series. Beds of limestone 

 also occur, though sparingly. The upper members where they 

 support the alpine limestone, pass into a calcareous conglome- 

 rate called in the Hartz and neighbouring districts, the Weisslie- 

 gende. This is by some authors considered as a distinct form- 

 ation ; by others (with whom I am inclined to agree), it is 

 included as the last deposit of the rotheliegende. 



Ores of iron, cobalt, and copper occasionally occur. 



The petrifactions of this rock appear to belong chiefly, if not 

 exclusively, to the vegetable kingdom. 



All circumstances indicate a near connection, but not an iden- 

 tity, of formation between the rothetodte and the great carboni- 

 ferous series.* It seems rather to hold an intermediate place 



* I have to add to the authorities I have previously adduced in confutation of the 

 arrangement which would identify the rothetodte and the old red sandstone of Britain, 

 that of Dr. Boue, particularly important, because he has minutely examined the 

 old red sandstone of Scotland, which, it has been contended (and principally on 

 the ground of his description), presented the closest analogies to the rothetodte, and 

 is equally acquainted with all the foreign localities of the latter rock, from recent jour- 

 nies. I have now a series of letters of the highest interest from this author to Prof. 

 Daubcny before me, in which he states, that " he agrees with Prof. Buckland in dis- 



