Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/51

 Rh clearly be understood, and an opportunity given to speculate upon the probable origin of these important strata. The southern parts of Lancashire, the northern extremity of Shropshire, and the whole of the intervening County of Cheshire, form in conjunction one vast tract of plain country, interrupted by few elevations, and these inconsiderable in size and extent. The area of this plain may be regarded as extending nearly fifty miles from north to south, and as having an average breadth of twenty-five or thirty miles. Its eastern boundary, as more immediately regards the County of Chester, is a high range of sandstone hills, stretching from north to south along the borders of Derbyshire and Staffordshire; connected on the north with the hills in the West Riding of York, and on their eastern side passing into the limestone hills of Derbyshire. The sandstone, in a considerable part of this range, is slaty in its structure, and would seem to belong to the Independent Coal-formation of Werner, some pretty extensive beds of coal being found and worked under it. The southern boundary of the plain, which is the one approaching most nearly to the rock-salt, is irregularly formed by ridges of limestone and calcareous sandstone, leaving open some communications with the level country in the middle of Shropshire. To the west its limits are marked by the sandstone and limestone hills in the adjoining part of Wales, and by the sandy estuaries of the Mersey and Dee. The only ridge of hills, properly speaking, within the Cheshire plain, is one on the western side of the county, extending with a few interruptions from Frodsham to Malpas, and including in its progress from north to south, the high grounds of Delamere Forest, the Hill of Beeston, and the Peckforton, Hills. This range, which no where attains an elevation of more than four or five hundred feet, is composed entirely of sandstone. A small quantity of copper ore has been found in the Peckforton Hills, which form its southern