Page:The South Staffordshire Coalfield - Joseph Beete Jukes - 1859.djvu/15

Rh from Derbyshire, ends on the north side of Charnwood Forest, while the Coal-measures overlap it and rest upon the Cambrian rocks. In Warwickshire no Carboniferous limestone makes its appearance. In South Staffordshire the Coal-measures rest directly upon Upper Silurian rocks. In the Coalbrookdale coalfield the Coal-measures resting towards the south on the Old Red Sandstone, overlap its termination towards the north, and repose upon Upper Silurian rocks, and further west, towards Church Stretton and the Breiddens, upon Lower Silurian and Cambrian rocks. Thin scraps of Carboniferous limestone, indeed, show themselves about Lillieshall, as if spreading just so far from Derbyshire, and also at the Clee Hills, as if dying out from South Wales, and the Old Red Sandstone likewise stretches from the latter direction, but thins out and terminates before reaching the Severn. It is clear then that the absence of the Old Red Sandstone and Carboniferous limestone from the narrow band of country before indicated, is due to causes operating during the deposition of those formations. They each died away and terminated as they approached it both from the north and the south.

Now these formations were deposited under water, the Carboniferous limestone certainly under the sea, as is shown by its being almost entirely made up of the remains of marine animals, it seems natural then to suppose that the area towards which they thus both thin out and terminate was not under water, but formed dry land. It is, in fact, almost certain, that whilst the sea flowed deep over the remainder of that space where England and Wales now exist, during the periods when the great formations of Old Red Sandstone and Carboniferous limestone were in course of deposition, & narrow promontory, or an island, or a group of closely connected islands ran in an east and west line across the district before pointed out. This land, however, must itself have been depressed either wholly or in part while the Coal-measures were being deposited, and as it slowly sank beneath the water, sheet after sheet of Coal-measures extended over it, till, perhaps, the whole neighbourhood was finally buried under one wide-spread subaqueous Coal-measure plain. Since that time it has not only been lifted up again, but broken, dislocated, and contorted by forces of