90 Mr. Weaver’s Geological Remarks. [Ave. 
this district porphyry and trap are also found in association with 
the coal formation, and that the same construction applies here 
as in the Petersberg tract. : 
If now called upon to draw a parallel between this carbonife- 
rous series and any of the British, I should say that here is ‘a 
general tract of old red sandstone, supporting on its eastern 
confines a coal district, which in many respects agrees with 
some of those of the Scotch great coal tract; while in the north- 
western and south-western quarters, the coal fields there appear 
to repose either immediately on transition rocks, or partly on 
these, and partly on old red sandstone, corresponding in this 
respect with some of the coal tracts in Shropshire, as well as in 
the circumstance of the absence of the carboniferous limestone. 
Tdo not perceive any ground that can be laid for considering, as 
it has been suggested, this range of sandstone as the millstone- 
grit and shale, (namely, the sandstone and shale interposed in 
some tracts between the carboniferous limestone and the great 
coal formation, properly so called), unless it could be shown to 
be divested of all those general characters of the fundamental 
aie of the old red sandstone, which it in fact so strikingly 
isplays. On the other hand, the absence of the millstone-grit 
and shale in Mansfeld and Thuringia is no greater anomaly there 
‘than it is elsewhere, e. g. in Cumberland, in most parts of Shrop- 
shire, in Ireland, and in the great coal tract of Scotland. Nor is 
it a greater anomaly that there but few beds of carboniferous 
limestone occur, since in some parts of our own island they are 
wanting altogether, e. g. in Shropshire. But this is not the 
whole of the question. What are we, strictly speaking, to 
understand by the term old red sandstone? I presume no one in 
the present day would confine it exclusively to the mere funda- 
mental bed of the carboniferous series. This would be as con- 
tracted a view, as if, in the case of gneiss alternating with beds 
of primary limestone, we were to restrict the use of that word 
to the lowest bed of gneiss. In the case then of the old sand- 
stone alternating with limestone, where is the line to be drawn ? 
Is it to be extended to the confines of the great coal formation, 
that is, when the latter is distinct? But who will separate one 
from the other, when, as in many cases in Scotland, the sand- 
stone, the limestone, and the coal, are repeatedly interstratified 
with each other? Were we indeed to take a large view of the 
subject, and to call the British carboniferous series the old or 
first great sandstone, formation or group, this expression would 
be quite equivalent to that of the rothe todtliegende, or first 
floetz sandstone, formation of Germany. In both countries, the 
~ subject matter is the same, though, from the fuller display of the 
seriesin the British Isles, the mode of considering and express- 
