John Randall — Geology of Linley Valley. 499 



coast-line. Towards the bottom of the Estuary the slope appears to 

 be less, for at Caughlej'^, over a mile frora the last point named, the 

 Clod coal, and the Little Flints, occasionally are found : but no trace 

 of them, as we have seen, is to be found at Linley Brook. How far 

 the extension of the Clod and Little Flint coals to Caughley, beyond 

 where we might naturally expect them to terminate, may be due to 

 a downthrow fault which intervenes, we cannot say ; but a great fault 

 crosses the road which lets down the brick and tile clays which are 

 on the surface, by Mrs. Thorn's brickworks, so that at the deep pits 

 near they are worked at a depth of ninety yards. 



If we follow the course of the Severn to the south, and examine 

 the rocks laid bare in the valley, and in channels cut by tributary 

 streams on either side, we not only find all traces of the older Coal 

 Measures disappear, but we find the younger members come in and 

 supply their place. 



If we cross the 16 miles area, consisting of the usual divisions of 

 the Permian, the Bunter, and Keuper sandstones, which separate 

 the coal-fields of Coalbrookdale and South Staffordshire, we find no 

 indications of the existence of the Coal Measures underneath ; on the 

 contrary, the experiments made at Enville, Shatterford, and other 

 places, demonstrate their absence. 



That the Shropshire and South Staffordshire coal-fields are frag- 

 ments of one mineral tract would appear from the position which 

 that important and persistent measure — the Pennystone Ironstone — 

 occupies in the two fields, as well as from the similarity of its 

 organic remains. The authors of the memoirs of the Geological 

 Survey, in their "Iron Ores of Great Britain," say that the lower 

 beds of the Coal Measures in South Wales and Shropshire (and the 

 same is true for Lancashire) contain a set of marine fossils, some of 

 which are Mountain Limestone species, and the rest peculiar to the 

 Coal Measui-es. Also, that there seem to be good reasons for sup- 

 posing the Eosser veins of South Wales equivalent to the Pennystone 

 and underlying ironstones of Coalbrookdale ; that the flat coal bass 

 has at least a very strong resemblance in its fish-remains to the 

 bottom vein ; and that the Darran Pins exactly resemble the white 

 flats of Coalbrookdale ; whilst the Ellea Balls Mine is the counter- 

 part of the ball stone of the same field. If the various beds of these 

 coal-fields can be correlated, and if it is reasonable to suppose that 

 the mineral seams originally extended over the greater portion of 

 the intermediate tracts where we know they no longer exist, the 

 extent to which they have been denuded is amazing. 



Still, when we look at the island-like form of the Brown Clee 

 Hills, rising above the sea of Old Eed Sandstone, and bearing on its 

 summit a narrow patch of the Lower Coal Measures — a mere wreck 

 saved by the protecting barriers of trap and other rocks from that 

 Titter destruction which befell the coal-seams spread over tracts 

 where now no trace exists — tlie mind is the moi'e disposed to believe 

 in the destruction of the Coal Measures from the eastern side of the 

 Shropshire field to the western side of that of South Staffordsliire 

 and East Worcestershire. 



