then not merely be separated by shales, but have a greater thickness of coal than it generally has farther south,) or else consider them as new coals not represented at all in the southern part of the field.
Whatever may be the truth with regard to those points of detail, the general fact of the beds at Essington. Wyrley, and Bentley, from the Old Robins coal down to Bentley Hay coal inclusive, being the representatives of the Thick coal can no longer be doubtful.
It appears that the materials which formed the shales and sandstone, &c. were deposited abundantly and frequently towards the north, but that some of them gradually became less and less towards the south, so that in many cases they finally came altogether to an end in the latter direction, while the coals were deposited equally, or nearly go, over both areas.
The fact now established is one of considerable interest, both as regards the practical working of this and other coal-fields, and as bearing on the theoretical explanation of the origin and formation of coal.
Note on the Fossils, by J. W. Salter, Esq.
The fossils of the ironstones as a whole very much resemble those of the Coalbrooke Dale coal-field. There is the same intermixture of marine shells, shark-like fish, and a few land plants, with a considerable number of unio-like shells (Anthracosia), too imperfect for determination in most cases. One species, however, is the A. bipennis. Brown, found, both here and in Flintshire, in the coal itself. The marine shells are quite the same as those of the "Pennystone" of Coalbrooke Dale, but they are fewer in number,
The following may be considered characteristic of the ironstones:— Discina (Orbicula) nitida of Phillips; Producta scabricula, Sowerby; a Lingula, which appears to be the L. elliptica of Phillips; Conularia guadrisulcata, and the two species of Myalina figured by Prestwich, viz. M. quadrata and M. carinata. The Aviculopecten scalaris, Sowerby, is rare. With these are abundance of the large fish defences, called Gyracanthus formosus, Agass.; scales of a large Holoptychius; the Megalicthys Hibberti; and Cochliodus. (Pæcilodus angustus occurs in bastard coal at the Fens colliery.) There are also traces of Annelides, and the usual plants, Lepidodendron, Calamites, &c., occur.
The localities from which these fossils have been obtained are;—the pit banks three-quarters of a mile N.E, of Portway Hall near Oldbury, and the Factory north of that place. The Producta and Conularia are abundant at the former, and the large Mytilus-like bivalves (Myalina), with the Lingula and Fish, at the latter.
South and south-west of Dudley, at Queen's Cross, Holoptychius and Myalina occur in the Gubbin ironstone; and at the Buffery ironworks the large Gyracanthus formosus. The Fens south-west of Dudley have a few shells in the carbonaceous bands, and also a fish-palate, Pecilodus angustus, a species equally characteristic of similar beds (the top coal) in Coalbrooke Dale. It is also found in coal in Flintshire.
Further west. Kingswinford colliery affords only Anthracosia, Modiola, and the Gyracanthus formosus. At Moor Lane, Brierly Hill, the Holoptychius and Lingula.
Further south, near Oldswinford, White Hall colliery has the usual Brachiopods, Lingula and Discina, with Conularia, Anthracosia bipennis (in coal), and the Aviculopecten scalaris.
Bare Moor colliery, only Brachiopods, Productæ, &c.
