.

Before we can decide on this question of transportation, we must know
whether the fossil coal-plants occurring in high latitudes bear the
marks of friction and of having decayed previously to fossilization.
Many appearances in our English coal-fields certainly prove that the
plants were not floated from great distances; for the outline of the
stems of succulent species preserve their sharp angles, and others have
their surfaces marked with the most delicate lines and streaks. Long
leaves, also, are attached in many instances to the trunks or
branches;[162] and leaves, we know, in general, are soon destroyed when
steeped in water, although ferns will retain their forms after an
immersion of many months.[163] It seems fair to presume, that most of
the coal-plants grew upon the same land which supplied materials for the
sandstones and conglomerates of the strata in which they are imbedded.
The coarseness of the particles of many of these rocks attests that they
were not borne from very remote localities, and that there was land
therefore in the vicinity wasting away by the action of moving waters.
The progress also of modern discovery has led to the very general
admission of the doctrine that beds of coal have for the most part been
formed of the remains of trees and plants that grew on the spot where
the coal now exists; the land having been successively submerged, so
that a covering of mud and sand was deposited upon accumulations of
vegetable mater. That such has been the origin of some coal-seams is
proved by the upright position of fossil trees, both in Europe and
America, in which the roots terminate downwards in beds of coal.[164]

To return, therefore, from this digression,--the flora of the coal
appears to indicate a uniform and mild temperature in the air, while the
fossils of the contemporaneous mountain-limestone, comprising abundance
of lamelliferous corals, large chambered cephalopods, and crinoidea,
naturally lead us to infer a considerable warmth in the waters of the
northern sea of the Carboniferous period. So also in regard to strata
older than the coal, they contain in high northern latitudes mountain
masses of corals which must have lived and grown on the spot, and large
chambered univalves, such as Orthocerata and Nautilus, all seeming to
indicate, even in regions bordering on the arctic circle, the former
prevalence of a temperature more elevated than that now prevailing.

The warmth and humidity