The coal-measures on the eastern side of this chain consist of the Northumberland, Durham, Yorkshire, Nottingham, and Derby fields; on the west and north, Whitehaven, Lancashire, Manchester, and North Stafford; and on the south lie the basins of Ashborne, Loughborough, Wolverhampton, and Dudley. The limestone skirts the out-crop of the metals in all these localities, and thus serves to define the relations of the several basins, and the cause of so many divisions in the field, occasioned by the net-work of coral reef with which it has been originally penetrated. The Wolverhampton basin is remarkable for the number of roots and stumps of fossil trees found “in situ;” in the Derby field the railway tunnel has exposed to view a group of sigillaria, forty in number, standing at right angles to the plane of the beds, and not more than three or four feet apart. Many of the tree fossils occupy a similar position in the Northumberland and Newcastle coal-measures, reminding us of the submerged forests of which, within the modern epoch, our sea-coasts furnish so many examples. The Newcastle coal-field embraces an area of nearly eight hundred square miles, being forty-eight miles in length by twenty-four in breadth; the depth of the shaft is about three hundred fathoms, from which are annually brought to the surface an average of six million tons of coal. Sixty thousand persons are employed in the mining operations; and fourteen hundred vessels are engaged in carrying the mineral to London and its environs. The iron trade, connected with the different English coal-fields, is upon a corresponding scale of magnitude, there being little short of a million and a half tons of the metal annually smelted and brought to the market, estimated to be worth, upon an average, twenty millions of pounds sterling, and comprising within the dimensions of this small island, as much as is exhumed by all the other nations of the globe. The Newcastle coal-measures have been singularly disturbed. A basaltic dyke, in some places eighteen yards wide, crosses the southern part of the field, throwing down the metals on one side ninety fathoms, and reducing the coal, at the distance of fifty yards, to a state of cinder. This great dyke is traceable through a course of seventy miles. As an example of the prodigious power with which these subterranean forces have acted in the district, suffice it to mention, that the limestone which underlies the coal metals has been elevated nearly to the summit of Cross Fell, a mountain three thousand feet in height; and estimating the thickness of the formation at four thousand feet, the limestone, it will thus appear, has been raised above its original position upward of six thousand feet.