THE FOSSIL FLORA. 
162 
whiMi present, are, in a majority of cases, terrestrial vegetables. 
The Carboniferous formation presents, from the lowest to the 
highest member, a series of the same vegetable forms. In the sand¬ 
stone beds, immediately succeeding tbe old red Conglomerate, which 
occurs at the base of the formation, along the line of the great Cross 
fell fault, Sigillaria, Lepidodendron, Calamites, and Stigmaria, begin 
to make their appearance; as we ascend, tbe vegetable remains in¬ 
crease, whilst those of marine animals, which existed in the lime¬ 
stone and shale in profusion, decrease, until we arrive at the Coal 
formation proper, where marine remains disappear, giving place to 
those of vegetables alone. 
In this part of the series, we have the remains of plants in every 
bed; the sandstones contain them, but, from the roughness of their 
mechanical composition, it is tbe larger and stronger stems only 
which have left their forms impressed upon rocks of this class. Coal 
itself very rarely retains any outward marks of its vegetable origin, 
but the shale bed, immediately over the coal, (when that substance 
forms the covering, as it usually does,) furnishes us.with fossils in 
the greatest abundance. These are exposed by the operations of the 
miner, who, in removing the coal, often brings to light vegetable 
forms of singular beauty and variety, which are almost invariably 
found parallel to tbe laminae of the stone, and pressed flat, their out¬ 
ward form being retained on the shale as it was taken by the soft 
mud which sealed them up, their substance being converted into 
coal. Very large stems are often found standing across the strata, 
and penetrating through several different beds. 
The vegetable origin of coal is now universally conceded; and it 
is almost as universally believed, that the plants, of the remains of 
which it is composed, were swept by torrents from some neighbour¬ 
ing high and dry land, into lakes and estuaries, where, becoming sa¬ 
turated with moisture, and loaded with sand and mud, they sank to 
the bottom, and there reposed upon previously deposited beds of sand 
and mud; another vegetable mass being in turn washed off, and bu¬ 
ried by successive deposits of these substances, to be followed, in due 
time, by another, and another. 
Associated with die seams of coal, and in the beds immediate! v 
surrounding them, stems of Sigillaria, of a large size, are frequently 
found standing erect, with their roots proceeding from them on all 
sides, (see Vol. 1, plate 54.) We are aware that the evidence of 
plants in this position having grown on the spots where we now find 
their remains, is not complete if taken alone, as it has been argued 
they have been floated from a distance, and left standing in an up- 
