[ 388 ] 
LIX. On the Mineral Structure of the South of Ireland^ *with 
correlative matter on Devon and Cornwall^ Belgium^ the 
Bifek By Thomas Weaver, Esq,, F.R.S., RG,S., 
M,R.I,A,^ 8^c, ^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 IBritish 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. Murchison f. From this author we had 
previously derived much valuable information concerning that 
region J ; 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 I now propose briefly to show, first 
introducing M. Dumont’s table of equivalents, for the sake 
of reference. 
Belgium, 
Terrain Houiller ‘ Coal Tract ’ 
, f Limestone. 
Upper calcareous J dolomite, 
system. [ Limestone. 
Upper quartzo- 
schistous system. 
Lower calcareous 
system. 
Lower quartzo- 
schistous system. 
Terrain Ardoisier. 
‘Slate Tract.’ 
r Sandstone. 
j Limestone subordinate, 
1 Schist. 
[ Limestone subordinate, 
p Limestone. 
J Dolomite. 
[ Limestone. 
C Grey fossiliferous schist, 
Schist and red sand. 
J stone. 
Conglomerate. 
Sandstone, quartz-rock, 
L schist, 
r Upper. 
J Medial. 
L Lower. 
England, 
{ Coal measures. 
Millstone grit. 
Carboniferous limestone. 
Old red sandstone. 
J Upper Ludlow rock. •) 
' I Aymestry limestone. \ forma 
J Lower Ludlow rock. S 
1. Wenlock limestone, 
. Wenlock shale. 
1 
Caradoc and Llandeilo formation. 
1 Wenlock 
J formation. 
] 
Cambrian 
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 V Academic Boyale des Sciences d Bruxelles, Novembre 1838; 
see also a translation of this Memoir in the bond, and Edinb. Philosophical 
Magazine for August 1839. 
X A. H. Dumont, Sur la Constitution Geologique de la Province de Liege, 
