The
name of _Permian_ was given to it by Sir Roderick Murchison,
from the province of Perm in Russia, where rocks of this age are
extensively developed. Formerly these rocks were grouped with
the succeeding formation of the Trias under the common name of
"New Red Sandstone." This name was given them because they contain
a good deal of red sandstone, and because they are superior to the
Carboniferous rocks, while the Old Red Sandstone is inferior.
Nowadays, however, the term "New Red Sandstone" is rarely employed,
unless it be for red sandstones and associated rocks, which are
seen to overlie the Coal-measures, but which contain no fossils by
which their exact age may be made out. Under these circumstances,
it is sometimes convenient to employ the term "New Red Sandstone."
The New Red, however, of the older geologists, is now broken up
into the two formations of the Permian and Triassic rocks--the
former being usually considered as the top of the Palaeozoic series,
and the latter constituting the base of the Mesozoic.
In many instances, the Permian rocks are seen to repose unconformably
upon the underlying Carboniferous, from which they can in addition
be readily separated by their lithological characters. In other
instances, however, the Coal-measures terminate upwards in red
rocks, not distinguishable by their mineral characters from the
Permian; and in other cases no physical discordance between the
Carboniferous and Permian strata can be detected.
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