100 UPPER COAL MEASURES OF COUGHLEY, TASLEY, ETC. 



field, being generally obscured by accumulations of drifted matter, or rendered difficult 

 of investigation by the numerous faults which run along the boundaries. To these 

 obstacles we may add, that no attempts like that of the Earl of Dartmouth (p. 58.) have 

 yet been made to follow out the coal beneath the red sandstone. If, however, we make 

 a transverse section from the coal works at Donnington across the hills on the east, and 

 pass near to Lilleshall Abbey, we see that where the works are nearest to the line of 

 red sandstone, the coal strata dip to the east or beneath the adjacent sandstone. This 

 coincidence of inclination in the red sandstone and coal measures may be observed at 

 several points between Lilleshall Abbey on the north (see section, PI. 29. fig. 15.), and 

 Prior's Lee on the south. Between Prior's Lee and the banks of the Severn near 

 Madeley the boundary is still affected by faults, but at Rowton near Broseley Mr. Prest- 

 wich has detected a passage from the upper carboniferous strata into the Lower New 

 Red Sandstone, similar to the one described in the Shrewsbury field. The same relations 

 are seen on the edge of a thin and broken zone of carbonaceous strata, which describing 

 a tortuous outline, ranges by Coughley to the Wren's Nest upon the right bank of the 

 Severn, and is thence deflected by Coal Moor into a low ridge extending from High 

 Trees to Tasley. At Tasley a single thin bed of impure and poor coal is worked by 

 windlasses, at depths varying from twelve to thirty yards. In the overlying strata is a 

 bed of limestone about three feet thick, identical with the freshwater limestone of the 

 Shrewsbury field. A section of these beds exposed in an open work near Tasley gives 

 the following succession. (PL 29. fig. 12.) 



ft. in. 



Green and yellow shale, decomposing to stiff clay, passing into a thick ferrugino-calcareous layer 6 0 



Limestone, compact and cream-coloured, with Microconchus carhonarius and Cypris. (The rock of Pon- 



tesbury and Le Botwood, see pp. 94 & 97 3 o 



Blue and grey shale 3 o 



Sandstone of greyish colour with carbonaceous matter and fragments of plants 4 0 



Blue bind or carbonaceous shale forming the top of coal 2 0 



Smut or impure coal 0 6 



Clod or argillaceous shale 0 2 



Coal 1 4 



Stiff mottled red and green shale, depth unproved. 



This coal contains in some parts thin laminae and veins of white calcareous spar. 

 It is further to be observed that much of the carbonaceous matter is in an uncon- 

 solidated state, exhibiting the matted fibres, leaves, and stems of the plants. This 

 structure, indicating an intermediate stage in the formation of coal, is not of un- 

 frequent occurrence in the upper secondary and tertiary carbonaceous deposits in va- 

 rious parts of Europe ; and although not often seen in the most ancient coal, I have 

 observed it in other parts of Shropshire and also in the Dudley field. 



The upper coal measures, reposing upon the Old Red Sandstone of Aldenham and Shirlot, dip 

 to the east, an inclination which would carry them directly beneath the Lower New Red Sandstone 

 of Cantern Bank and Astley Abbots if they were not met by the prolongation of what Mr. Prestwich 



