1823.] On the principal Mountain Chains of Europe. 135 



Article IX. 



Memoir illustrative of a general Geological Map of the principal 

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

 FRS. &c. 



{Continued from p. 16.) , 



[Some copies of* the map having been, in the haste of publica- 

 tion, incorrectly coloured, the reader is requested to compare the 

 colours with the dotted outlines. Where they do not coincide, 

 the former are erroneous : the errors are generally f a nature 

 which will admit a ready correction by these means. It will be 

 seen that some parts of the present article are taken from a 

 former publication by the same author.] 



Carboniferous Series. 



The carboniferous series, considered in the largest acceptation 

 of the term, comprises, besides the coal measures properly so 

 called, certain other formations of limestone and sandstone, so 

 associated with them, that the attempt to separate them would 

 materially interfere with the clearness of a natural division. 



1. The coal measures, properly so called, consist of numerous 

 alternations of seams of coal with beds of slate clay and sand- 

 stone. 



2. These repose on an alternating system of shale and grit, in 

 which the peculiar limestone characterising the coal districts 

 makes its first appearance in any considerable quantity. The 

 coal seams here become few and unimportant. 



3. A system succeeds characterised by the predominance of 

 the limestone called, from its relation to the coal fields, carboni- 

 ferous. The coal seams in this system are reduced to slight 

 traces which have never yet been worked. 



4. A vast deposit of quartzose conglomerate and sandstone, 

 commonly called old red sandstone, forms the lowest formation 

 in this great natural order. No coal has yet been observed in 

 or below this formation.* 



5. Trap rocks of various kinds (basalt, greenstone, porphyry, 

 and amygdaloid) occur associated with the preceding formations 

 in various modes of combination, as dykes, irregularly interposed 

 or overlying masses, and sometimes as alternating beds. The 

 phenomena are such as often to render it doubtful whether they 

 are of cotemporaneous origin with the rocks among which they 



* The case of Portishcad Point cited by Mr. Weaver as affording an example of this 

 position in erroneous ; the coal is there associated with the regular sandstone of the coa 

 measures, and reposes very distinctly on the great carboniferous limestone. Mr. W 

 who had not visited the place himself, was misled by an incorrect report. I hav 

 repeatedly examined the spot in company both with Prof. Scdgewick and Prof. 15uck 

 land. 



