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 A HISTORY OF STAFFORDSHIRE SILURIAN SYSTEM In the adjoining county of Shropshire the Pre-Cambrian, Cambrian, Ordovician and Silurian formations follow each other in natural con- secutive order. Of these only the Silurian emerges in Staffordshire, from under the intervening Red Rocks, on the crests of the three anticlines of Sedgley Beacon, Dudley Hills and Walsall. The complete sequence of the sediments composing this essentially marine deposit, the oldest of the county, does not occur in any one of the three localities ; yet by piecing together the information obtained in one district with that in another it is found that, excepting the initial stages represented by the Lower Llandovery sub-formation and that of the final close of the period (Ludlow Passage Beds), there is present, in the heart of the South Staffordshire Coalfield, a typical development of that most famous of British formations the Silurian. In one of its stages, that of the Wenlock, the district of Dudley has become especially celebrated both on account of its furnishing Murchison with material for his great work on the Silurian system and also for the abundance of typical fossils, excellently preserved. Upper Llando'very or May Hill Sandstone. The first deposits of the Silurian seas indicate shallow water conditions. They afford a very limited exposure, and that only in the Walsall area, where they con- sist of pale yellow, brown, or occasionally white sandstones poorly representing the littoral and sub-littoral deposits of the Upper Llan- dovery or May Hill Sandstone of the Welsh borderland. Among other fossils the characteristic brachiopods Stricklandinia /ens, S. Strata, and the trilobite Encrinurus punctatus are not uncommon. Barr Limestone. The May Hill Sandstone is closely followed by a band of richly fossiliferous limestone, well known to local geologists from its containing at Hay Head, in the parish of Barr, fine examples of a trilobite Ilcenus barriensis a fossil characteristic of the Woolhope Limestone of other Silurian regions, and to which the Barr Limestone, as it is locally known, corresponds. The limestone was formerly extensively quarried, but little opportunity of obtaining fossils now exists. Wenlock Limestone and Shale. The next overlying sub-division con- sists of slightly consolidated dark blue and grey mudstones and shales about 800 feet thick, at the summit of which lie two bands of limestone (Wenlock Limestone] separated by about 800 feet of shale. The lower shales are inclined at gentle angles in the Walsall area, and consequently cover a considerable extent of ground. They are not well exhibited in sections, but abundant fossils chiefly brachiopods and corals can be obtained in the railway cutting at Five Lanes. The limestones occur only in the western extremity of the inlier and are exposed in the rail- way cuttings within the town of Walsall and in some old quarries in the neighbourhood. In the Dudley Castle Hills and Wren's Nest the Wen- lock strata are bent up into an elongated dome dislocated by faults. The 4