The most remarkable seam of the South Staffordshire coalfield is that known as the Ten yard or Thick coal, a continuous bed of workable coal from 25 to 30 feet in thickness. This underlies all the south central part of the field in the area enclosed by Smethwick, Oldbury, Dudley, Walsall and Bilston. To the southward near Halesowen it thins out and becomes mixed with shaly material. It is in reality composed of 13 or 14 superimposed coal seams, which form an apparently unbroken mass, but are easily distinguished individually by the practised Thick coal miner. As we pass northward from the typical Thick coal area towards Walsall and Cannock Chase, the component seams become separated by intercalated sandstones and shales, so that eventually in the district of Essington and Pelsall the Thick coal is represented by 14 distinct coals occurring at intervals in a mass of sandy rock, between 500 and 600 feet in total thickness. The Thick coal is known to extend far to the eastward, beyond the present margin of the South Staffordshire coalfield. The first attempt to reach it through the red ground (Permian) was made under the bold and skilful guidance of the late Mr. Henry Johnson, C.E., of Dudley, at the locality of Sandwell Park. The coal was reached in 1873 at a depth of 1,250 feet and found to be of its original thickness, and of excellent quality. The next attempt which was made at Hamstead Hall, about three miles outside the limit of the coalfield, was even bolder and more hazardous, but it was eventually crowned with equal success; the Thick coal being reached at a depth of 1,800 feet. As the demand for coal increases, other collieries will doubtless be started at fresh localities outside the limits of the coalfield, for there can be no question that the Thick coal extends far to the eastward, under and beyond the town of Birmingham itself. The strata of the South Staffordshire Coalfield afford the usual fossils of the British Coal Measures. The roofs of the coal seams, and the layers of carbonaceous shale, locally furnish well preserved examples of _Lepidodendron_, _Sigillaria_, _Calamites_, _Annularia_, _Pecopteris_, _Neuropteris_, etc., often associated with abundant specimens of the peculiar _Unio_-like shell, _Anthracosia_: while the ironstone nodules occasionally yield fragmentary _Crustaceans_ and _Insects_. Marine fossils are principally confined to the lower beds of the series, below the Thick coal. Owing to the absence of true limestone beds in the coalfield, the characteristic corals, &c., of the Carboniferous are absent, but the following marine forms are not uncommon in the lower ironstones:-- _Lingula elliptica_, _Discina nitida_, _Producta scrabicula_, _Conularia quadrisulcata_, _Aviculopecten scalaris_, _Gyracanthus farmosus_, _Megalichthys Hibberti_, _Pœcilodus angustus_. These have been met with at several localities near Walsall, Oldbury, Old Hill, Kingswinford, and Oldswinford, etc.