The Forest of Wyre and the Titterstone Clee Hill Coal Fields
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( 999 ) XXVII.—The Forest of Wyre and the Titterstone Clee Hill Coal Fields. Introduction. By Dr R. Kidston, F.R.S. Part I: The Geology of the Forest of Wyre Coal Field. By T. C. Cantrill, B.Sc, F.G.S.—The Fossil Plants of the Forest of Wyre Coal Field. By Dr R. Kidston. Part II: The Geology of the Titterstone Clee Hill Coal Field. By E. E. L. Dixon, B.Sc, F.G.S.—The Fossil Plants of the Titterstone Clee Hill Coal Field. By Dr R. Kidston. With an Appendix on The Fossil Plants collected from the Core of the Claverley Trial Boring. By Dr R. Kidston. (With Five Plates and Six Text-figures.) (Read June 28, 1915. MS. received January 24, 1916. Issued separately March 9, 1917.) INTRODUCTION. The investigations recorded in this communication were begun some years ago, and arose chiefly as the result of two papers published on the Geology of the Forest of Wyre by Mr T. C. CANTRILL, B.SC* In the latter paper Mr CANTRILL, after carefully summarising all the available data respecting the age of the so-called " Permian " of the Forest of Wyre (= Enville), arrives at the following conclusions :— I. That these " Permian" rocks are of the same age as those at Hamstead in South Staffordshire. II. That the Hamstead red rocks were shown by their flora to be Upper Coal Measures. He therefore concludes that " the evidence of the fossil flora and the Spirorbis- limestones and coal-seams in South Staffordshire, together with that of the Spirorbis-limestone and coals in the Wyre Forest district, leads us to regard the associated red rocks as Upper Coal Measures. ." t In his paper entitled "A Contribution to the Geology of the Wyre Forest Coal- field, etc.," he further says on p. 16: "The Wyre Forest Coalfield contains two sets of Coal Measures— " A younger [grey] group, probably of Upper Coal Measure age. " An older [grey] group, probably of Middle Coal Measure age." * "A Contribution to the Geology of the Wyre Forest Coalfield, and of the Surrounding District," 8vo, Kidder- minster, 1895 ; "On the Occurrence of Spirorbis-Limestone and Thin Coals in the so-called Permian Rocks of Wyre Forest; with Considerations as to the Systematic Position of the ' Permians' of Salopian Type," Quart. Journ. Geol. Soc, vol. li, p. 528, 1895. + Quart. Journ. Geol. Soc, vol. li, p. 547. TRANS. ROY. SOC. EDIN., VOL. LI, PART IV (NO. 27). 142 1000 DR R. KIDSTON, MR T. C. CANTRILL, AND MR E. E. L. DIXON. On p. 19 of the same paper, under the heading of "Upper Coal Measures," he further states :— " These form almost the whole surface of the coalfield except the districts indi- cated. They consist of yellow, buff, and orange sandstones, shales and marls, of great similarity to the upper parts of the Halesowen Sandstones of South Stafford- shire. They contain many thin pyritous coals and several poor ironstones. The two most important and constant coals are the Brock Hall seam and the Main Sulphur seam, between which lies the Spirorbis Limestone." Since these remarks were written, now twenty years ago, much has been done to elucidate the geology of these so-called " Upper Coal Measures." When writing my paper on the Fossil Flora of the Potteries Coal Field in 1891, I referred all the " Red Measures " which lay above the Spirorbis limestone that occurs 12 yards above the Bassey Mine ironstone to the Upper Coal Measures,* and these, I understand, are the same series of rocks to which Mr CANTRILL referred his " Upper Coal Measures " of the Wyre Forest. It was only through subsequent study of the fossil plants of these so-called Upper Coal Measures that it was seen that much of this series of rocks must be regarded as passage-beds between the true Upper Coal Measures (= Radstockian Series) and the Middle Coal Measures (= Westphalian Series), and for these the name of Transition Series was proposed.! The lowest of the beds that were classed by the Geological Survey as Permian, and referred by Mr CANTRILL to the Upper Coal Measures, have now been identified with the Keele Group, and belong to the true Upper Coal Measures or Radstochian Series.,\ When the name " Transition Series " was proposed for these passage-beds, the occurrence of this series in the Potteries Coal Field was pointed out; but up till that time they had yielded very few fossil plants, and in the absence of this guidance I failed to discover the important place they held in North Staffordshire, and selected as my type areas for the Transition Series the Lower Pennant Rocks of the South Wales Coal Field and the New Rock and Vobster Groups of the Somerset Coal Field. It is, however, to Dr WALCOT GIBSON § that we are indebted for our intimate knowledge of the Transition Series as developed in North Staffordshire, and of the three groups of which it is. composed. These are, in descending order :— I. Newcastle-under-Lyme Group. II. Etruria Marl Group. III. Black Band Group. * Trans. Roy. Soc. Edin., vol. xxxvi, p. 63, 1891. See especially pp. 65 and 68. t Vroe. Roy. Phys. Soc. Edin., vol. xii, p. 228. 1894. I See Quart. Journ. Geol. Soc, vol. lxi, 1905, p. 320. § Memoirs of the Geological Survey of England and Wales: The Geology of the North Staffordshire Coalfields, 1905, p. 51. FOEEST OF WYRE AND TITTERSTONE GLEE HILL COAL FIELDS. 1001 The overlying Keele Group, as already mentioned, I refer to the true Upper Coal Measures ( = Radstockian Series), of which it is the basal part. At a later date, the name Staffordian Series was substituted for the earlier term "Transition Series" which had been applied to these rocks.* This alteration in nomenclature was suggested chiefly from two considerations : firstly, that the term "Transition Formation" had been used for rocks of Lower Carboniferous or Culm age, and, though in that sense the term seems to be now out of use, its employment might lead to confusion ; t and secondly, as the series is so well represented in Staffordshire, and has been so fully described in the northern portion of that county by Dr GIBSON, it was more appropriate to name it after the area where it had been most fully worked out and could be best studied. It was with these rocks, then, which we now call Staffordian Series, that CANTRILL correlated the rocks he described in the Forest of Wyre under the name of " Upper Coal Measures." This correlation holds good to-day, if we remember that the Keele Group, also present in the Wyre Forest, is retained in the Upper Coal Measures. It will also be seen that CANTRILL was right in referring the Lower Coal Group to the Middle Coal Measures (= Westphalian Series). The present investigations were instituted with the object of determining which groups of the Staffordian Series are present in the Wyre Forest Coal Field, and to ascertain if the Keele Group could be shown by fossil evidence to be present in the area. Though the latter of these questions we have not been able to solve on palseontological grounds, some advance has been made in the elucidation of the other points, as well as in adding to our knowledge of the fossil flora of British Carbon- iferous rocks. PART I. THE GEOLOGY OF THE FOREST OF WYRE COAL FIELD. In ordinary circumstances it would not be necessary, in what is mainly a palaeo- botanical paper, to enter into a detailed geological description of the district. But as the Wyre Forest Coal Field, though mapped on the one-inch scale by the Geological Survey over fifty years ago, has not been described in any official memoir, it has been thought advisable to lay before the student a brief account of the strati- graphical sequence and geographical distribution of its various Carboniferous divisiens. The reader will thus more readily appreciate the problems that -still await solution. The Forest of Wyre Coal Field \ commences at Bridgnorth, on the Severn, in * Quart. Journ. Oeol. Soc, vol. lxi, p. 320, 1905. t See GOPPERT, Floram fossilem Formationis Transitionis = Die fossile Flora des l/bergangsgebirges, Breslau, 1852. + The coal field is included in the Old Series One-Inch Geological Maps, Sheets 61 S.E. (1852-55, revised 1868) and»55 N.E. (1853-55), and in the New Series One-Inch Ordnance Maps, Sheets 167 and 182. It covers parts of Shropshire, Worcestershire, and Staffordshire. 1002 DR R. KIDSTON, MR T. C. CANTRILL, AND MR E. E. L. DIXON. Shropshire, where the Coalbrookdale Coal Field reaches its southern limit. There is no complete break between the two, but the outcrop of the Coal Measures is reduced to a narrow band between the Old Red Sandstone on the west and the so-called Permian rocks on the east. From Bridgnorth the Coal Field extends southward, broadening out till it reaches the latitude of Bewdley, in Worcestershire, beyond which it is cut off on the south by the emergence of the Lower Old Red Sandstone of Heightington. In the south-west a narrow neck of Coal Measures, half a mile broad, connects this main northern area with a peninsular portion, which extends in a south-eastward direction from Bayton as far as the Silurian ridges of the Abberley Hills. To these two portions must be added the anticlinal tract of Trimpley, where a broad fold of the Old Red Sandstone is bounded on each side by a narrow strip of Coal Measures. These strips run from near Bewdley in a north eastward direction for about 5 miles, and unite in the neighbourhood of Compton, where the Coal Measures of the Forest of Wyre are separated from those of South Staffordshire by a distance of only 5^ miles.