Chap. VI.] 
THE WENLOCK LIMESTONE. 
115 
in the lowest part of the Wenlock group, these forms being essentially character- 
istic of the Lower Silurian rocks. Oornulites serpularius, PI. XVI. f. 6, and other 
Annelides are sometimes found, as well as stems and portions of Encrinites, 
though the perfect fossils are very rare in the typical region. With respect to 
Corals, it may be stated generally that they are the same as those of the Wen- 
lock limestone, but fewer in number, — the Cup-corals Cyathophyllum, Om- 
phyma, &c, with Favosites alveolaris, and Stenopora fibrosa, being the most 
conspicuous. Graptolithus priodon, which is a most abundant and characteristic 
fossil of the Wenlock shale, has been already figured as occurring in the Lower 
Silurian rocks, Foss. 12. f. 3, and PI. XII. f. 1, 2. 
Wenlock Limestone. — The upper member of the formation is a lime- 
stone, usually of lighter grey colours than the lower calcareous band 
already described under the name of Woolhope or Lower Wenlock. Al- 
though it is in every respect identical with the well-known limestone of 
Dudley, I named the rock after the sharp rectilinear ridge of Wenlock 
(see Map), because its relations to inferior and superior deposits are there 
better seen than in any other part of the British Isles, as exhibited in this 
sketch. 
Wenlock Edge. 
Wenlock Edge, as seen prom the Hills op overlying Ludlow Eock 
on the S.W. (From Sil. Syst.) 
The Valley of Apes Dale, 1, on the extreme left, is in the Wenlock shale. The linear 
ridge, 2, is the limestone of Wenlock Edge, dipping under the higher ridge, 3. of 
Ludlow rocks, which also occupy the foreground. 
The Wenlock limestone consists of thick-bedded, grey, subcrystallinc 
limestone, very rarely of light-pink colour, and in parts argillaceous. In 
other parts of the Wenlock Edge, the rock is more crystalline ; and where 
varied colours prevail, the matrix being charged with Encrinites and Corals, 
it forms a pretty marble, though the slabs are of no great dimensions. 
The mass is essentially of a concretionary nature, and thus differs much 
from the flat-bedded Lower Wenlock or Woolhope limestone, being for 
the most part marked by nodules of small size. Occasionally, however, 
the concretions are large, and are then locally termed ' ballstones.' 
This limestone is underlain and overlain by shale of pale-grey and 
greenish tints, copiously charged with small nodules of argillaceous lime- 
i 2 
