[ 388 ] 



LIX. On the Mineral Structure of the South of Ireland^ isoith 

 correlative matter on Devon and Cornvoall^ Belgium^ the 

 Eifel, Sfc. By Thomas Weaver, Esq., F.R.S., F.G.S., 

 M.R.I. J., Sfc. 4-c. 



[Continued from page 297.] 



A S a conclusion to this paper, and as connected with my 

 ■^^ subject, I am tempted to advert to the disposition so pre- 

 valent among geologists of placing in parallel British with fo- 

 reign formations, without always maturely considering all their 

 respective peculiar relations. As a case in point, none comes 

 more readily to my hand than the late attempt of M. Dumont 

 to assimilate the transition tracts adjacent to the Rhine, ex- 

 tending; from the north of France through Belgium into Ger- 

 many*, to the Cambrian and Silurian systems of Professor 

 Sedgwick and Mr. Murchisonf. From this author we had 

 previously derived much valuable information concerning that 

 region;]: ; but the parallel since drawn by him between the 

 Belgian and British formations is the more remarkable, as it 

 is confessed that the two countries do not correspond in the 

 development of the mineral masses, nor yet in the distribution 

 of organic remains. Nay, so far as the latter have hitherto 

 been ascertained, there appears to be but a slight analogy 

 between them, and which 1 now propose briefly to show, first 

 introducing M. Dumont's table of equivalents, for the sake 

 of reference. 



Belgium. England. 



1: ... ■ rr -11 _ I r•^.^ T.^^i > ( Coal measures. t S 



I Terrain HouiUer 'Coal Tract' 1 MiUstone grit. 1 g . 



i „ 1 „ r Limestone. f L <2i S 



Upper calcareous I jj^lomite. -^ Carboniferous limestone. faU 



system. |^ Limestone. L l§ |- 



Old red sandstone. J S 



r Sandstone. T n t ht u - ^ 



Upper quartzo. I Limestone subordinate. I ^PP^^e'st^y Hmest'one ' I L^d^^ 

 schistous system. ) Scliist. f ■, ;;.„„, TiiHlnw rnrk C formation. 



' I Limestone subordinate.J -^"^^^"^ Ludlow rocK. 3 



T , r Limestone. -1 



^°";""1'="'=°"^/ Dolomite. I Wenlock limestone. "l ^ , ^ 



system. i Limestone. J L Wenlock I W 



{ Grey fossiliferous schist. Wenlock shale. J ™rniation. r c 



Schist and red sand- - 

 stone. I 



Conglomerate. v, Caradoc and Llandeilo formation. 



Sandstone, quartz-rock, [ 

 schist. J 



Terrain Ardoisier, J HPSfJ," 1 J Cambrian 



^ 'Slate Tract.' j ^I^^^^f; | | system. 



* For a connected view of these tracts, it will be useful to refer to the 

 "Geognostic Map of Germany and the adjoining States," published by 

 Schropp and Co., Berlin, 1826. 



f Bulletin de I'Academie Royale des Sciences a. Briixelles, Novembre 1 838 ; 

 see also a translation of this Memoir in the Lond. and Edinb. Philosophical 

 Magazine for August 1839. 



X A. H. Dumont, Sur la Constitution Geologique de la Province de Liege, 



< 



