430 



ENCIRCLING WENLOCK AND LUDLOW ROCKS. 



Low, wooded hills surround the shale (c 1 ) . These are composed exclusively of the 

 Wenlock limestone (c of wood-cut) , a solid mass of which generally rises to near the 

 top of the ridge, accompanied with the usual small concretionary nodules. This zone, 

 the chief seat of the limeworks of the district, has a valley on each side, the inner 

 one excavated in the Wenlock, the outer in the Ludlow shale. 



To describe the zoological remains of this limestone would be only to repeat accounts 

 given of them in other places, a vast number of the characteristic fossils of the forma- 

 tion being present. (See PI. 12, 13 and 14 and descriptions.) These organic remains, 

 particularly the corals (PI. 15 and 16.), are most abundant at Fownhope, Winslow Mill 

 and Lindels. The inclination of the beds of limestone is for the most part higher than 

 that of the inferior strata. At Winslow Mill they dip 40°. At Fownhope they are 

 thrown up to 40° and 50°, and at Lindels, where the opposite ridges unite and terminate 

 in an apex, they incline 30° to 40°. 



The exterior ridge is composed of the Ludlow formation, which is thrown off on all 

 sides from the central and inferior rocks, plunging beneath the Old Red Sandstone. 

 These Ludlow rocks preserve their usual tripartite subdivision into a lower shale (6 s ), 

 a central calcareous stratum or the Aymestry rock (&') and Upper Ludlow rocks (&). 



The shale (Z> 2 ) occupies a valley, separating the harder parts of the formation from the 

 Wenlock limestone, &c. The higher part of this shale rises into the steep escarpments 

 of the outer rim, and passing into an argillaceous sandstone, is undistinguishable from 

 the " mudstone " of Abberley or " pendle " of Shropshire. 



The calcareous or central member (& 1 ) is the equivalent of the limestone of Aymestry, 

 and with the exception of that peculiar shell, the Pentamerus Knightii, it contains the 

 well known fossils of the stratum, such as Terebratula Wilsoni, Lingula Lewisii, Turbo 

 cor allii, &c. (See PL 6.) 



From its greater hardness, this rock has resisted denudation more effectually than 

 any other portion of the formation, and therefore constitutes the culminating points. 

 It is used for road making, and at one or two places was formerly burnt ; but the su- 

 perior quality of the adjoining Wenlock limestone supersedes this application of the 

 stone. It forms the crest of the external ridge of the Woolhope Valley, and in Marcle, 

 Seager, and Backbury Hills, rises above all the deposits of the included valley. 



The calcareous beds pass insensibly into the overlying argillaceous sandstone or 

 Upper Ludlow rock (6 of wood-cut), which to the east and north sides, descends 

 into the plain, at angles varying in the different promontories from 35° to 15°, the dip 

 usually decreasing towards the low and fertile region of the Old Red Sandstone. 



The western and south-western face of the ellipse, or the ridge extending from Mor- 

 diford to Fownhope, is an exception to this gradually decreasing inclination from the 

 lower to the upper strata of the Ludlow rock, that portion of the margin being thrown 

 up at the high angle of 60° to 65°. The actual junction of the Ludlow rock along this 

 frontier with the Old Red Sandstone, is for the most part obscured by detritus, which 



