Murchisons Silurian System. 37 



spirited undertaking of the Earl of Dartmouth," already 

 alluded to, to sink through them for coal. " These workings 

 descended through a variety of red and spotted sandstones, 

 blotches deep red, and variegated marls, and thick courses of 

 red calcareous grit, concretions of impure limestone (corn- 

 stone) and ferruginous deep red, hard, calcareous sand- 

 stone ; the fissures in the rock being sometimes coated with 

 crystals of coloured pink sulphate of barytes and sulphate of 

 iron. At my last visit the shafts, then at a depth of two 

 hundred yards, were passing through a light red micaceous 

 sandstone, in which blotches of ferruginous marl were mixed 

 with grains of carbonaceous matter. Some of the layers of this 

 rock were separated by laminae of black mica ; concretions 

 of calcareous sandstones as round as cannon balls, occurred at 

 intervals, and altogether there was so much calcareous matter 

 as to give the rock a very concretionary aspect. The reader 

 will perceive that these are the very same strata which overlie 

 the coal in natural sections at other places, and hence there 

 could be little difficulty in predicting that coal measures would 

 be found beneath them, particularly as it is well known that the 

 coal seams of the adjacent field of Dudley do not deteriorate or 

 thin out in the vicinity of these works, but are simply faults. 

 " The existence of the upper beds of coal having been as- 

 certained by borings carried down to a depth of more than 

 seven hundred feet below the surface, they (and the lower 

 beds) have since been reached by sinkings, an account of which 

 with a full description of the strata passed through, will be 

 given in the chapter on the Dudley coal-field. In the east- 

 ern parts of Shropshire, between Enville and Bridgenorth, 

 the Lower Red Sandstone occupies low terraces and depres- 

 sions beneath the calcareous conglomerate, and at Shatter- 

 ford is conterminous with a thin band of coal measures. 

 The uppermost strata are so very similar to those of the 

 great mass of rock above the calcareous conglomerate, that 

 the description of the one may almost serve for that of the 

 other. Thus, for example, in the cliffs opposite Bridgenorth, 



