a 
Subdivisions of the Paleozoic Strata of Great Britain. 353 
Fourthly. There is in like manner, in some localities, a great 
difficulty in drawing the demarcation between the Carboniferous 
and Permian series. This difficulty was acknowledged by Smith 
or did the progress of discovery remove this difficulty: for 
hear Whitehaven many true carboniferous fossil plants have been 
found in the Permian sandstone which underlies the magnesian 
imestone ; and similar fossils have also, I believe, been found in 
the Permian sandstone of Yorkshire. 
Again, asa prevailing rule, both in the northern and south- 
Western English counties, the Permian groups (as before stated) 
are unconformable to the carboniferous. But in central Englan 
this rule fails. Thus, in the coal-fields north of Coventry there 
is a fine Permian sandstone which is perfectly conformable to the 
coal-strata, partakes of their accidents, and appears to pass into 
them.t On the contrary, it is overlaid discordantly by the gyp- 
Seous marls, sandstones, &c. of the Triassic group. 
Pifthly. There is a similar difficulty is drawing a fixed line of 
demarcation between the Permian and ‘Triassic groups. In 
Yorkshire, where the Permian series is most perfectly developed, 
its upper beds are parallel to, and (through some red gy pseous 
beds) seem to form a good mineral passage into the Triassic 
Series. And on the coast of Cumberland, geologists are not 
agreed where to draw the line between the two great groups— 
Permian and Triassic. Sir R. I. Murchison has drawn the line 
above the red sandstone of St. Bees’ Head. I think this is a 
Mistake, and that the line ought to be drawn below that red 
Sandstone; which is, I believe, the equivalent of the Bunter 
stein, or Grés rouge of the Trias. wal ; 
After the remarks above made (under the five preceding heads) 
let no one suppose that I have any wish materially to change the 
Pty A work not without some errors, but of very great merit considering the early 
€ of its publication (1821). : ; ae 
: y . sieving ei perbaps, be considered inaccurate, when ths a 
that (in the coal-fields alluded to) the Carboniferous series is separated vee 
Permian sandstone by one, and sometimes two, thin bands of limestone (exactly li 
We thin bands described jin the Silurian eS es Se ae 
which ar pose . rigin ver be their origin, 
(in romps YW d to be of freshwater of! with true car iferous plants. 
45 
