The name “Permian” was proposed by Sir Roderick I. Murchison, in the
year 1841, for certain deposits which are now known to terminate upwards
the great primeval or Palæozoic Series.[50]
[50] See “Siluria,” p. 14. _Philosophical Mag._, 3rd series, vol.
xix., p. 419.
This natural group consists, in descending order, in Germany, of the
Zechstein, the Kupfer-schiefer, Roth-liegende, &c. In England it is
usually divided into Magnesian Limestone or Zechstein, with subordinate
Marl-slate or Kupfer-schiefer, and Rothliegende. The chief calcareous
member of this group of strata is termed in Germany the “Zechstein,” in
England the “Magnesian Limestone;” but, as magnesian limestones have
been produced at many geological periods, and as the German Zechstein is
only a part of a group, the other members of which are known as
“Kupfer-schiefer” (“copper-slate”), “Roth-todt-liegende” (the “Lower New
Red” of English geologists), &c., it was manifest that a single name for
the whole was much needed. Finding, in his examination of Russia in
Europe, that this group was a great and united physical series of marls,
limestones, sandstones, and conglomerates, occupying a region much
larger than France, and of which the Government of Perm formed a central
part, Sir Roderick proposed that the name of Permian, now in general
use, should be thereto applied.
Extended researches have shown, from the character of its embedded
organic remains, that it is closely allied to, but distinct from, the
carboniferous strata below it, and is entirely distinct from the
overlying Trias, or New Red Sandstone, which forms the base of the great
series of the Secondary rocks.
Geology is, however, not only indebted to Sir Roderick Murchison for
this classification and nomenclature, but also to him, in conjunction
with Professor Sedgwick, for the name “_Devonian_,” as an equivalent to
“Old Red Sandstone;” whilst every geologist knows that Sir R. Murchison
is the sole author of the SILURIAN SYSTEM.
[Illustration: XII.--Ideal landscape of the Permian Period.]
The Permian rocks have of late years assumed great interest,
particularly in England, in consequence of the evidence their correct
determination affords with regard to the probable extent, beneath them,
of the coal-bearing strata which they overlie and conceal; thus tending
to throw a light upon the duration of our coal-fields, one of the most
important questions of the day in connection with our industrial
resources and national prosperity.
On the opposite page an ideal view of the earth during the Permian
period is represented (PL. XII.). In the background, on the right, is
seen a series of syenitic and porphyritic domes, recently thrown up;
while a mass of steam and vapour rises in columns from the midst of the
sea, resulting from the heat given out by the porphyries and syenites.
Having attained a certain height in the cooler atmosphere, the columns
of steam become condensed and fall in torrents of rain. The evaporation
of water in such vast masses being necessarily accompanied by an
enormous disengagement of electricity, this imposing scene of the
primitive world is illuminated by brilliant flashes of lightning,
accompanied by reverberating peals of thunder. In the foreground, on the
right, rise groups of Tree-ferns, Lepidodendra, and Walchias, of the
preceding period. On the sea-shore, and left exposed by the retiring
tide, are Molluscs and Zoophytes peculiar to the period, such as
_Producta_, _Spirifera_, and _Encrinites_; pretty plants--the
_Asterophyllites_--which we have noticed in our description of the
Carboniferous age, are growing at the water’s edge, not far from the
shore.
During the Permian period the species of plants and animals were nearly
the same as those already described as belonging to the Carboniferous
period. Footprints of reptilian animals have been found in the Permian
beds near Kenilworth, in the red sandstones of that age in the Vale of
Eden, and in the sandstones of Corncockle Moor, and other parts of
Dumfriesshire. These footprints, together with the occurrence of
current-markings or ripplings, sun-cracks, and the pittings of
rain-drops impressed on the surfaces of the beds, indicate that they
were made upon damp surfaces, which afterwards became dried by the sun
before the flooded waters covered them with fresh deposits of sediment,
in the way that now happens during variations of the seasons in many
salt lakes.[51] M. Ad. Brongniart has described the forms of the Permian
flora as being intermediate between those of the Carboniferous period
and of that which succeeds it.
[51] A. C. Ramsay, “On the Red Rocks of England.” _Quart. Jour. Geol.
Soc._, vol. xxvii., p. 246.
Although the Permian flora indicates a climate similar to that which
prevailed during the Carboniferous period, it has been pointed out by
Professor Ramsay, as long ago as 1855, that the Permian breccia of
Shropshire, Worcestershire, &c., affords strong proofs of being the
result of direct glacial action, and of the consequent existence at the
period of glaciers and icebergs.
That such a state of things is not inconsistent with the prevalence of a
moist, equable, and temperate climate, necessary for the preservation of
a luxuriant flora like that of the period in question, is shown in New
Zealand; where, with a climate and vegetation approximating to those of
the Carboniferous period, there are also glaciers at the present day in
the southern island.
Professor King has published a valuable memoir on the Permian fossils of
England, in the Proceedings of the Palæontographical Society, in which
the following Table is given (in descending order) of the Permian system
of the North of England, as compared with that of Thuringia:--