598 
MR. E. W. BINNEY ON SOME LOWER-COAL-SEAM EOSSIL PLANTS. 
leaves, which are not so well shown in the Plate as they are generally found on speci- 
mens of Sigillaria organum. No doubt it cannot be regarded as a good example of the 
species organum , but from the ribs, furrows, and scars on its outside no one will question 
its being a Sigillaria , even if its internal structure did not prove its relationship to 
Sigillaria elegans. 
In all my investigations as to the origin of coal, the marine character of the water in 
which the plants that formed it by their decomposition grew, becomes to my mind more 
evident. It is now well known to all parties conversant with coal-mining, that in most 
deep mines where the surface water cannot get down the water found in the coal is 
quite salt, and contains iodine, bromine, and the usual constituents of sea-water. Any 
person carefully examining each of the seams of coal in which the fossil woods described 
in this memoir were found, placed as they are upon an under clay full of Sigillaria- roots 
with their radicles traversing it in every direction, will be convinced that the plants 
which formed the coal grew on the spot where it is now met with, and were not drifted 
there, while the presence of such a mass of marine shells as is found in the roof of each 
seam evidently where they lived and died, equally proves the salt nature of the water. 
Little evidence is to be obtained of the character of the dry land of the Carboniferous 
epoch except what is afforded by a few sun cracks on some of the rocks, but from the 
shallow seas more resembling marine swamps than the oceans of the present day, it was 
probably little above the surface of the water. Shallow seas and low lands would of 
course greatly influence the climate of the period. The strata found in the vicinity of 
seams of coal, with some few exceptions, show that they were deposited from water 
during periods of great tranquillity, and the vast range over the old and new worlds of 
the genus Sigillaria found in all their true coal-fields, indicates a uniformity of condi- 
tions of which we have now no parallel, and areas of such immense extent as is only 
equalled by some of our present oceans. 
In the Lancashire coal-field, probably one of the best developed in Great Britain, 
from the bottom to the top there are about 120 different seams of coal, great and small. 
These indicate 120 periods of rest or repose of the earth’s crust, when a primeval forest 
reared its top above the waters until the vegetable matter now forming each bed of coal 
was grown and deposited*. Then such forest was submerged and buried under mud 
and sand now found as shale and sandstone rocks. The hollow caused by such subsi- 
dence was silted up until it was again covered by shallow water. Then, again, a fresh 
crop of vegetation flourished so as to form another bed of coal. For 120 different times 
did this successive growth of vegetable matter, submergence and silting up go on. In 
some instances whole forests oi Sigillaria, standing upright in fine shale, on the top of the 
seams of coal are met with, thus clearly showing that they were submerged quietly and 
slowly, whilst at other times the prostrate stems now found lying in sandstone roofs 
* Although upright Sigillarice are generally found in the roof of a seam of coal, they are also met with in fine- 
grained shales, midway between seams, less frequently in coal floors, and more rarely still in the seams of coal 
themselves. — Transactions of the Manchester Literary and Philosophical Society, vol. viii. 2nd series, p. 176. 
