42 Murchisori s Silurian System. 



have been opened in this rock to the depth of thirty feet, exposing a 

 hard greenish and deep red sandstone, in parts calcareous, in others 

 slightly concretionary and conglomerated, the whole subordinate to 

 stiff red, argillaceous marl or shale. Here, as at Cantern Bank, near 

 Tasley, the beds lie conformably upon the coal strata, a band of which 

 appears below in the bed of the Severn, while the superior face of the 

 red rock dips beneath the overlying conglomerate of Apley Terrace. 

 As Mr. J. Prestwich, to whose labours in this coal-field I shall have 

 occasion to allude hereafter, has discovered plants in these Lower Red 

 Sandstones, the analogy to strata of similar age near Hales-Owen, 

 Hagley, Shrewsbury, and other places is complete. 



" On following this rock to Coal-Port Bank, we there see it exhibited 

 in deep vertical sections. Thick and thin bedded, red, argillaceous sand- 

 stones, yellowish and greenish grits, occasionally calcareous, with way- 

 boards of argillaceous marl, constitute the upper cliff, dipping to the 

 east 10° under an argillaceous cover, and resting upon thick bedded red 

 sandstone, having a slight tendency to conglomerate structure. The 

 other varieties of this rock contain rounded grains of quartz, and white 

 specks, probably of decomposed felspar, with little iron pyrites in a 

 calcareous paste, together with bands of coarse-grained, pebbly grit, and 

 specks of chlorite, in a cement of white crystallized carbonate of lime. 

 Some of the calcareous grits enclose concretions of green and red marl, 

 thus resembling the impure cornstones of the Old Red Sandstone. Between 

 Coal-Port and Madeley this sandstone is affected by powerful faults, to 

 the chief of which I shall advert in a subsequent chapter; it being 

 enough for my present purpose to state, that along the boundary of 

 this field, as in Staffordshire, great dislocations equally affect the carbo- 

 niferous strata and the Lower New Red Sandstone !* A transverse 

 section from Sturchley to Shifnal, across Nedge Hill, like those previ- 

 ously cited, exposes sandstones and flaggy grits, both green and red, 

 and thin courses of slightly calcareous conglomerates and flagstones, 

 associated with much argillaceous marl ; the whole passing beneath the 

 younger group of Shifnal, &c. The country around Shifnal, Sheriff- 

 Hales, and Crackley Bank, is covered with the quartz pebbles of the 

 disintegrated conglomerate, beneath which a dark coloured, finely 

 laminated, soft sandstone is seen at intervals ; but these beds, as well as 



* These are all elaborately described by Mr. J. Prestwich, in whose Memoir, 

 preparing for publication in the Geological Transactions, will be found -valuable 

 details of the dislocations of the carboniferous and associated strata in this vicinity. 



