INTRODUCTION. XxIx 
Society*;” in which, on physical grounds, I classed the Magnesian limestone (now called 
Permian Series) with the New Red sandstone (now Triassic) Series; while on paleontological 
grounds it was far more nearly connected with the Carboniferous. 
Nor did the progress of discovery remove this difficulty: for near Whitehaven many 
true Carboniferous fossil plants have been found in the Permian sandstone which underlies 
the Magnesian limestone; and similar fossils have also, I believe, been found in the Permian 
Sandstone of Yorkshire. 
Again, as a 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 England 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 acci- 
dents, and appears to pass into themt. On the contrary, it is overlaid discordantly by the 
gypseous marls, sandstones, &c. of the Triassic group. 
Fifthly. There is a similar difficulty in 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 gypseous 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 sandstein, or Gres rouge of the Trias. 
After the remarks above made (under the five preceding heads) let no one suppose that 
I have any wish materially to change the nomenclature of the Paleozoic Series as sketched 
in the Tabular View. Whatever may become of the three Divisions of the Paleozoic Series— 
whether they be retained as they are, or admit of a new adjustment—very little affects any 
important question of classification and nomenclature: but I see no ground for anticipating 
that the subdivisions into Cambrian, Silurian, Devonian, Carboniferous, and Permian, will ever 
require any material change or adjustment: at least so long as we continue to adopt a 
geographical nomenclature, which is based on the actual succession of physical groups and is 
* Second Series, Vol. III. pp. 121 and 122. The following words occur in these pages: “ Notwithstanding the entire 
break which, in many parts of England, exists between the coal-measures and the superior deposits, in certain parts of 
Yorkshire there is no such want of continuity; and the Lower Red sandstone (Permian) seems to form a connecting link 
between the carboniferous order and the group of the New Red sandstone (Trias). Moreover the fossils of the Magnesian 
limestone have little resemblance to the fossils of the Lias and the Oolites; but have several genera and species in common 
with the mountain limestene.” If the word species be struck out (or given as doubtful) this quotation will very nearly 
represent the truth: and I well remember my surprise when I first saw the Palzozoic type (to adopt the present 
nomenclature) of the Magnesian limestone fossils, and the reluctance there was, on the part of some others, in first admitting 
the fact. For at that time most English geologists regarded the Carboniferous rocks as Transition; while all of them 
were agreed in regarding the New Red sandstone and its dolomites as Secundary. 
{ The words “to pass” may, perhaps, be considered inaccurate, when it is added, that (in the coal-fields alluded to) the 
Carboniferous Series is separated from the Permian sandstone by one, and sometimes two, thin bands of limestone (exactly 
like the thin bands described in the Silurian System, in the same geological position) which are supposed to be of fresh- 
water origin. Whatever be their origin, they are (in the country alluded to above) associated with true Carboniferous 
plants. 
