Murchisori s Silurian System. 39 



To the south and north of Bridgenorth the lower beds of 

 New Red, as exposed on both banks of the Severn, are similar 

 in all respects to those described elsewhere, consisting of 

 brownish, red, argillaceous and calcareous sandstone, flaglike 

 calcareous grits, with occasional underlying, slightly red and 

 yellowish sandstones, not unlike certain coal grits. Before, 

 however, we take leave of this tract, a little more detail is 

 called for, respecting the relations of the Lower New Red to 

 the south of Bridgenorth, where the formation has been 

 generally confounded with the Old Red Sandstone ; though 

 it is clearly separated on many points from that system by a 

 zone of coal measures. Such is distinctly seen at Chelmarsh, 

 where a ridge consisting entirely of the Lower Red Sand- 

 stone and associated beds of calcareous concretions, overlies 

 in conformable opposition, and graduates downwards into 

 strata, containing seams of coal. The descending order on 

 the western slope of Chelmarsh Common is as follows : — 



1. Red Sandstones passing into calcareous conglomerates, 

 sometimes of concretionary structures. 



2. Argillaceous marls and clay, with beds of whitish sand- 

 stone, occasionally with green grains. 



3. First traces of coal measures, viz. dark and grey shale 

 and light coloured sandstone, with seams of coal, too poor 

 to be worked. 



4. Top coal of this district twenty-two inches thick, the 

 highest bed in use. 



5. Calcareous concretions of grey and green colours, 

 resembling certain varieties of the cornstone of the Old and 

 New Systems ; a band of this limestone is seen in the bed of 

 the Borle Brook, dipping under the top coal. 



6. Lower coal, two feet six inches thick, with associated 

 measures, lies at some depth beneath the limestone, but is 

 not now in work. 



All these beds, from the lower coal to the overlying red 



