428 J. PrestwicHj Esq., on the 



The following is a list of the more abundant fossils obtained by myself: 



Bellerophon aj)ertus, Sow. ; Leptcena hemispherica, Sow. ; Leptcena gigantea. Sow. ; Terehra- 

 Uda saccula, Phil. ; Syringopora ramulosa, Phil. ; Lithostrotion floriforme, Fleming ; Cyathophyl- 

 lum ; Favositest septosuStVhW. (See also Appendix, List of Organic Remains). 



In the foregoing pages, I have confined my observations to the range and 

 structure of the formations underlying the coal-measures, deferring all re- 

 marks on the dislocations by which they are affected to a subsequent chapter, 

 in which I purpose to describe the faults and their accompanying phenomena. 

 The probable distance to which the different underlying formations may ex- 

 tend below the coal-measures, will be considered in the conclusion. I will 

 now proceed to the examination of the coal-field of Coalbrook Dale — a field, 

 characterized by the variety and singularity of its organic remains, as well as 

 by the great disturbances which it has undergone. 



COAL MEASURES. 

 PI. XXXV. and XXXVL, figs. 1 to 14, and 16. 



Owing to the hilly nature of the country, some excellent sections of the 

 coal-measures are exhibited. On the sides of the deep gorge through which 

 the Severn flows from the Iron Bridge to Bridgenorth, the coal-measures, 

 the Wenlock limestone, and new red sandstone, are well exposed. At Woom- 

 bridge, Lawley, and Coalmoor, are several open works of the Penneystone 

 and sulphur coal. The flint-coal sandstone, so full of fine vegetable remains, 

 is extensively quarried at Ketley. The lowest strata crop out in the side of 

 the road at the top of the Dale, also at Steeraways, the Hatch, the Dunge, 

 near Broseley, and in the various dingles south of the Severn. The upper 

 strata are more rarely exposed. The heaps of the different ironstones at the 

 pit's mouth afford, especially when long exposed, excellent opportunities for 

 obtaining organic remains. 



The measures are composed of the usual alternations of shales, sandstones, 

 and coals, with, occasionally, subordinate calcareous beds. In the upper part 

 of the series, unproductive marls, shales, and slightly calcareous, thick-bedded 

 sandstones predominate ; and in the lower part, shales containing ironstones, 

 hard sandstones, sometimes conglomeratic, and numerous seams of coal. The 

 colours of the upper strata are generally light gray, yellow, or red ; some of 

 the central beds are extremely dark, whilst the colours of the numerous lower 

 sandstones are usually very light. Such are the general lithological charac- 

 ters; but they are subject to considerable local variations, which will be de- 

 tailed hereafter. 



It is difficult to state accurately the total thickness of the coal-measures, as 

 there is no shaft section in which the entire series from the new red sand- 



