Geological Societjj. 491 



much resembling a large inverted ship, of which Serlgeley Beacon, 

 630 feet above the sea, may be considered as the keel. The u])per 

 Ludlow rock, though not thick, is plainly marked by containing the 

 Leptcena lata, the Seipula gigantea, &c., and by overlying a limestone 

 which is in every respect identical with that o{ Aymcstreij or the middle 

 member of the Ludlow rocks, presenting the same lithological struc- 

 ture, i. e a dull argillaceous grey limestone, which among other well- 

 known shells, such as the Terthratnla IVihoni and the Lingula, con- 

 tains also the beautiful Fentamerus Knighlii so entirely peculiar to this 

 stratum. As at Ludlow and Avmestrev, this limestone of Sedgeley, 

 known here as the " black limestone," forms an excellent cement 

 under water. 



'I'urner's Hill, a small elevation between Gornals and Himley, is 

 coniijosed of Lufllow rocks; and the Hayes is a narrow short tongue 

 of the same, with a central band of limestone, which rises at a high 

 angle from beneath the coal measures, on the main road from Stour- 

 bridge to Flales Owen, a portion of the lower Ludlow rock being also 

 well exposed. 



2a. " li'enlock limestone." — This limestone formation is much more 

 largely developed than that of the Ludlow rocks, constituting several 

 ellipsoidal masses near the town of Dudley, which have been long 

 worked, and extensively known among collectors, from the number 

 and beauty of their organic remains. Hence the rock has been usually 

 termed the " Dudley limestone." As, however, it was im])ossible to 

 have ascertained in this district the relative age of these rocks, their 

 different members being independently in contact with the coal mea- 

 sures, the nomenclature of tiie Silurian system already selected is ad- 

 hered to, because in Shropshire the Wenlock limestone, in its fullest 

 standard, rises out regularly from beneath the Ludlow rocks, and the 

 latter passing beneath the old red sandstone and carboniferous lime- 

 stone (both of which are wanting at Dudley) complete the |)roofs re- 

 quired. The author therefore entreats geologists not to employ the 

 term Dudley limestone except as the synonym of Wenlock, with which 

 he proceeds to show its lithological and geological identity. This 

 limestone is described in detail at the Castle Hill, Wren's Nest, and 

 Hurst Hill, in all of which it forms ellipsoidal elevated masses, 500 to 

 650 feet high, protruding through the coal measures in lines paral- 

 lel to similarly shaped masses of Ludlow rock at Sedgeley j &c., i. e. 

 trending from lO'E.ofN. to 10° VA^. of S. Two strong bands of 

 limestone occur in these hills, overlaid and separated from each other 

 by shale, charged with numerous small concretions of impure lime- 

 stone, the " bavin" of the workmen. The limestone having been quar- 

 ried out from these bands which have been raised up from a common 

 centre, and disposed with a quaquaversal dip at high angles, it is evi- 

 dent that the hills themselves would ere now have been demolished, 

 had they been composed throughout of calcareous masses of equal 

 purity ; but the " bavin" or refuse composes the framework of these 

 perforated hills, and preserves their outline. The Wenlock shale, or 

 underlying part of the formation, constitutes the nucleus of the 

 Wren's Nest, the largcbt ami most jjerfect of these ellipsoids, anil 

 of this the author gives a detailed plan. These ellipsoids usually 

 .'3 N 2 



