70 SUPPLEMENT TO THE 



in colour ; and this is also a character of the beds on the same horizon on the flanks of the 

 Longmynd, exposed in the cuttings of the Craven-Arms and Bishops-Castle Railway, 

 eighteen miles to the west of the Buildwas-Park Sections. 



" These soft shales have largely determined the configuration of the contours of the 

 district, and represent the sweeping Ape-Dale Valley of denudation, which spreads out 

 for twenty miles below the supporting ridge of Wenlock Limestone of Wenlock Edge, 

 and in Coalbrook Dale have yielded to the excavation of that picturesque valley. 



" Some soft shales, about 100 feet thick, overlying the Wenlock Limestone, and 

 exposed in cuttings by the side of the railway between Buildwas and Wenlock, west of 

 the Bradley Lime-quarries, may also pertain to the Wenlock series : in physical character 

 they more nearly resemble the shales of the Wenlock than the overlying Ludlow Beds. 



"The Wenlock Shale in Shropshire, which cannot be much less than 1800 to 1900 

 feet in thickness, has a development much in excess of the Wenlock Shale in the Malvern 

 district, where Professor Phillips estimated it to be 640 feet thick ; indeed, its thickness 

 in Shropshire is greater than in any other district, unless we except its supposed 

 equivalents, the Denbighshire Flags, which I believe will be found to belong to a 

 distinctly lower horizon. 



" The Ludloio Series. — Any definite estimate of the relative thicknesses of the several 

 members of the Ludlow Beds is difficult to arrive at, as at the eastern extremity of the 

 Shropshire escarpment the Aymestry horizon is ill-defined, here and there represented by 

 isolated thin bands of limestone, and again as thick masses of impure concretionary 

 limestone intermixed with shale. Collectively the Ludlow series attains a thickness of 

 from 1200 to 1400 feet, which the Aymestry band divides nearly equally; the Lower 

 Ludlow being a little thicker than the Upper, and consisting of softer shales. The Upper 

 Ludlow Beds, as at Burton, near Wenlock, often assume the character of fissile tile- 

 stones. The Lower Ludlow Beds are exposed in cuttings of the Wenlock Railway 

 between Wenlock and Presthope, and the very base of these beds is seen in the Wenlock 

 Railway east of Wenlock. The equivalent of the Aymestry Limestone is finely exposed 

 in the road-cutting below the Dunge House, near Broseley, and to the west of the Marsh 

 Earm on the high road between Broseley and Much Wenlock. The Upper Ludlow is to 

 be seen by the roadside at Burton, near Wenlock, and is also exposed in Willey Park, 

 and in the bottom of the valley below the Dean Farm, near Broseley. 



" The beds connecting the Upper Ludlow with the Old Red Sandstone, which are 

 well exposed on the banks of a little stream known as Linley Brook, two or three miles 

 south of Broseley, have been described by Messrs. Roberts and Randall in the * Quarterly 

 Journal of the Geological Society of London,' vol. xix, p. 229. The upper part of their 

 section, given at p. 232, appears to refer to the base of the outlier of the Coal-measures, and 

 the remainder to the base of the Old Red Sandstone and top of the Upper Ludlow. The 

 red micaceous marls in the road-cutting on the Bridgnorth side of the valley clearly 

 belong to the Old Red Sandstone, and these, I suppose, are represented by the bed 



