403 
Devon and Cornwall, Belgium, the Eifel, ^c. 
types are mere general results founded on actual observation, 
it is obvious that they can never upset conclusions drawn from 
the clear and unambiguous evidence of sections. The two 
methods may be used independently, and conspire to the 
same end, but in their nature connot come into permanent 
collision'^.” In the present case it should be borne in 
mind that the consecutive series of the older stratified rocks 
of the south of Ireland is unconformably overlaid in the 
northern parts of Kerry, Cork, and Waterford, directly 
either by the t7'ue old red sandstone formation of British 
geologists, or by the carboniferous limestone, or the coal for- 
mation f. 
I might now extend the comparison by entering into the 
countries adjacent to the right bank of the Rhine, or into 
the Fichtelgebirge ; but in neither of them is the informa- 
tion hitherto obtained of so extensive and detailed a character 
as to admit of precise conclusions. To what was previously 
known respecting the former tracts, M. Beyrich has made 
considerable additions in his Beitrdge\ and from these con- 
tributions it may be collected, that the greater part of the 
Nassau limestones near Dillenburg, &c., as well as those of 
Bensberg, Refrath, Palfrath, &c., adjoining the Rhine, to- 
gether with the greywacke and slaty rocks in which they are 
intercalated, or on which they simply rest, exhibit in general 
the same organic remains as the Eifel, although they possess 
also species and even genera not hitherto found in the latter; 
e. g., at Palfrath the genera Nerita, Megalodon, Cardita, 
Monodonta, Buccinum\ and in Nassau in the Wissenbach 
clayslate Parmophorus \ and in the limestone on the Lahn near 
Villemar an Ostrea, a genus not previously noticed in any 
transition country. Of the Nassau limestones it is remarked 
that they differ chiefly from the Eifel limestone by being for 
the greater part interstratified with the greywacke and slate 
rocks, while the limestones of the Eifel are merely superim- 
posed upon the latter in troughs. In Belgium, however, the 
same, namely, the lower limestone of that country, forms an 
interstratified portion of the general series. Considering then 
the fossils which have been noticed in these districts, we have 
here again an exemplification of affinities and differences in 
the organic types of their respective strata. Should M. 
Beyrich complete the work which he proposed to himself in 
the year 1837, of drawing up an exact critical catalogue of 
* Proc. of Geol, Soc., vol. ii., p. 675, May 1838, [or bond, and Edinb. 
Phil. Mag. vol. xiii., p. 299. 
t See niy Geological Map of the South of Ireland, in Geol. Trans, 
vol. V., second series. 
