OUTLIERS OF LUDLOW ROCKS. 



241 



above the sea. Tinker's Hill rises on the south-west from the left bank of the Teme, near the 

 Saltmoor Well, and is chiefly composed of Upper Ludlow rock, the strata of which, though dip- 

 ping only 5° or 6° to the south-east at the south-western or low end of the hill, are thrown up to 

 angles of 40° and 45°. By this upcast a band of the Aymestry limestone is brought out on the 

 escarpment, and was formerly much worked, being in some quarries about forty feet thick. It con- 

 sists principally of small nodules enveloped in sandy calcareous shale, but occasionally united into 

 thick flaglike beds of grey or bluish earthy limestone. This sandy and argillaceous limestone is 

 much preferred to the purer limestones as a sub-aqueous cement, and for ceiling and plaster. 

 Among the fossils is the Terebratula Wilsoni and others characteristic of the limestone, though I 

 have not found the Pentamerus Knightii. This shell, so prevalent in the main escarpment, be- 

 comes very rare in the denuded patches on the exterior slopes of the Ludlow rocks, as they descend 

 towards the Old Red Sandstone in the vicinity of Ludlow, (Whitcliffe Woods, Sunny Bank, Palmer's 

 Cairn, &c. &c.) ; its disappearance therefore in an outlier still further removed from the principal 

 range of the rock is what might be expected. There can, however, be no doubt of the age of this 

 limestone, for at Caynham Bridge the strata pass up into true Upper Ludlow rock charged with 

 most of its peculiar fossils. The gorge in which the Lutwiche traverses the ridge, is a disruption 

 of the strata, for on the right bank, a large mass of limestone is thrown across the prevalent direc- 

 tion, dipping 35° south-south- west ; whilst in Caynham Camp on the left bank, the north-easterly 

 strike is preserved, and the same rocks are at a different level dipping to the south-east. The north- 

 eastern extremity of the hill, on which was the ancient camp, is round, the strata dipping inwards 

 with much contortion. In consequence of the destruction and denudation of the surrounding strata, 

 there are no evidences of the precise relations of this ridge of Ludlow rocks to the Old Red Sand- 

 stone through which it has been upcast, except on the side of the brook between Poughhill and 

 Caynham Bridges, where the Old Red Sandstone is highly inclined ; and again in a small knoll be- 

 tween Steventon and Tinker's Hill, where red and green marls and red sandstone are almost ver- 

 tical, thus affording proofs that their dislocation was affected by the movement which elevated the 

 ridge of Ludlow rocks, since similar beds of Old Red Sandstone appear on the adjoining banks of the 

 Teme, resting at very low angles and undisturbed, upon the Upper Ludlow rock. 



The saline well in the flat at the south-western end of Tinker's Hill, issues most probably from 

 the Ludlow rock, as it is in a line between the ridge described and a part of the bed of the Teme 

 in which the same strata emerge from the thick cover of gravel and clay which overlay them in the 

 neighbourhood of the well. 



Two other small contiguous outliers of Ludlow rock, occur on the right bank of the Severn near 

 the southern termination of the coal-field of Coalbrook Dale. The most southern rises from 

 beneath the Old Red Sandstone at Lindley, and throws off to the north-east and north-west poor 

 and thin coal measures. The more northern and more prominent of the two is nearly two miles 

 long, and about a quarter broad, extending from Dean on the west-north-west, by Darley and 

 Frith Coppice to near the Severn on the east-south-east. This mass is flanked by the upper coal 

 measures containing the freshwater limestone, (see p. 100.) At Dean Corner the beds consist of 

 thin lenticular masses of impure limestone and shale, probably equivalents of the Aymestry lime- 

 stone. They contain Terebratula Wilsoni and other fossils, and dip at a low angle under the coal 

 measures. On the sides of the woody Frith Dingle, the same and also lower strata are exposed in 

 horizontal layers, some of which are sandy and flaglike, and seem to represent the Upper Ludlow 

 rock \ others consist of flattened slightly calcareous spheroids, inclosing Terebratula JVilsoni s 

 T. affinis, &c. 



