JOURNAL OF The Russell Society Volume 21, 2018 www.russellsoc.org JOURNAL OF THE RUSSELL SOCIETY The journal of British Isles topographical mineralogy JOURNAL EDITORS David Green Malcolm Southwood 61 Nowell Lane, Leeds, 7 Campbell Court, Warrandyte, West Yorkshire, LS9 6JD, U.K. Victoria 3113, Australia. JOURNAL MANAGER Frank Ince 78 Leconfield Road, Loughborough, Leicestershire, LE11 3SQ, U.K. EDITORIAL BOARD R.E. Bevins, Cardiff, U.K. M.T. Price, OUMNH, Oxford, U.K. R.S.W. Braithwaite, Manchester, U.K. M.S. Rumsey, NHM, London, U.K. A. Dyer, Hoddlesden, Darwen, U.K. R.E. Starkey, Bromsgrove, U.K. N.J. Elton, St Austell, U.K. P.A. Williams, Kingswood, Australia. I.R. Plimer, Kensington Gardens, S. Australia. Aims and Scope: The Journal publishes refereed articles by both amateur and professional mineralogists dealing with all aspects of mineralogy relating to the British Isles. Contributions are welcome from both members and non-members of the Russell Society. Notes for contributors can be found at the back of this issue, on the Society website (www.russellsoc.org) or obtained from the Journal Editor or Journal Manager. Subscription rates: The Journal is free to members of the Russell Society. The non-member subscription rates for this volume are: UK £13 (including P&P) and Overseas £15 (including P&P). Enquiries should be made to the Journal Manager at the above address or via the Society website (www.russellsoc.org). Back numbers of the Journal may also be ordered through the Journal Manager. The Russell Society: named after the eminent amateur mineralogist Sir Arthur Russell (1878–1964), is a society of amateur and professional mineralogists which encourages the study, recording and con- servation of mineralogical sites and material. For information about membership, please refer to the Society website (www.russellsoc.org) or write to the Membership Secretary, Neil Hubbard, 30 Thirlmere Road, Barrow-upon-Soar, Leicestershire, LE12 8QQ. Printed by: Flexpress Ltd, 8 Coal Cart Road, Interchange, Birstall, Leicester, LE4 3BY. Published by: The Russell Society. Registered Charity No. 803308. Copyright: Whilst the Russell Society retains the copyright to the printed journal, the copyright of the text is not necessarily held by the Society. Permission to reproduce any text, figures or photographs from the published articles must be obtained from the Journal Editor. The views and opinions expressed in this journal are not necessarily those of the Journal Editor, the Society or the Editorial Board. ISSN 0263 7839 FRONT COVER: A group of colourless, transparent baryte crystals (6×2 mm) with overgrowing rhombohedral dolomite from Hickleton Colliery, Thurnscoe, South Yorkshire. Specimen 149 in the Steve Uttley Collection; photo John Chapman. BACK COVER: A group of white, translucent, prismatic calcite crystals (34 mm across) from the Whin Sill at Barrasford Quarry, Gunnerton, Northumberland. Peter Briscoe Collection; photo David Green. Journal of the Russell Society CONTENTS Volume 21, 2018 EDITORIAL 2 ERRATUM 2 PAPERS Late-stage hydrothermal mineralisation of the Whin Sill: a review 4–16 Brian Young and Andy Hopkirk Millerite from Linton Quarry, Gorsley Common, Herefordshire 17–20 Roy E. Starkey and Tom F. Cotterell Andradite and magnetite in contact-metamorphosed chalk near Portmuck, Islandmagee, County Antrim 21–26 Norman R. Moles Mineralisation in the Coal Measures of Yorkshire and adjoining areas 27–92 Richard Bateman, Peter J. Briscoe, John Chapman, David I. Green and David McCallum The post-Acadian, Lower Palaeozoic hosted base-metal vein mineralisation of Snowdonia and 93–105 the Llŷn Peninsula, North Wales John S. Mason Andradite-bearing skarn-like mineralisation and a suspected palaeogene dyke from Coed y Brenin, 106–123 North Wales John S. Mason, Martin Liezers and Tom F. Cotterell BOOK REVIEWS “Minerals of the English Midlands” by Roy E. Starkey 124–126 David Green “Mountain Movers: mining, sustainability and the agents of change” by Daniel M. Franks 127 Norman Moles Journal of the Russell Society (2018) 1 EDItorIAL TOPOGRAPHIC MINERALOGY Is mineralogical publication ‘in the pink’? Volume 1 part 1 of the journal dropped onto doormats in March 1982. The late Bob King, our first journal editor, noted that: “... the need for such a journal has long been felt where accomplished amateur mineralogists might present scientifically important observations, both on systematical and topographical mineralogy ... which might be unacceptable to the current professionally orientated scientific journals”. The key phrase here is ‘topographic mineralogy’. Since its inception, the journal has recorded mineralisation at localities in the British Isles. In so doing, many rare and unusual species have been reported, their relationship to the local geology recorded, theories on how they may have formed offered and collections described. And after thirty-six years of publication there is still no shortage of important localities to describe! Information in mineralogy, as in many other scientific subjects, is organised in hierarchies. Individual specimens and their labels are the foundation on which everything else is built. The value of gluing a small label with locality details to every important specimen is emphasised in a recent newsletter article by Tom Cotterell. Specimens are organised into collections, and if these are assembled thoughtfully, the whole (which may have an accompanying field notebook, photographic archive, catalogue or database) is much more than the sum of the parts. The information contained in collections provides data for articles. Late-stage hydrothermal mineralisation associated with the Whin Sill of northern England is described in a geological context in an account which includes images of specimens, mostly in the Brian Young Collection, photographed by Andy Hopkirk in the first article of this journal. Tom Cotterell and Roy Starkey have contributed an account, of millerite from Gorsley Common. Rediscovered after more than a century, in an area not known for its minerals, the value of careful detective work is shown. Skarn mineralisation containing euhedral andradite, reported seventy years ago by G. P. L. Walker near Portmuck in County Antrim, is described by Norman Moles. The article includes several excellent photos of specimens from Norman’s collection by a new Society member John Chapman. John Mason and colleagues emphasise the geological context of mineralisation in Wales, in two articles, one of which includes a note on the ‘magnificent uralite porphyry’, an intriguing rock, which like the Gorsley Common millerite, has been rediscovered after many years of obscurity. The importance of collections and careful specimen curation is shown by Richard Bateman and colleagues in a discussion of the minerals of the South Yorkshire Coalfield. An attempt is made to provide a holistic description of the mineralogy of a relatively large area, in a study which is based on a small collection, a few published articles, and the data in two privately printed manuscripts assembled by the late Steve Uttley. In mineralogy, the top of the information pyramid is occupied by topographic books, grand syntheses of published data which describe large regions. When volume 1 part 1 of the journal came through members’ letterboxes in 1982, British topographic mineralogy was anchored in the nineteenth century. The standard topographic work was the Manual of the Mineralogy of Great Britain and Ireland (Greg and Lettsom, 1858). This has since been replaced by Minerals of Britain and Ireland (Tindle, 2008) and augmented by a number of well illustrated volumes which deal with the mineralogy of smaller regions. This year sees the publication Minerals of the English Midlands. Roy Starkey’s work will need little introduction to most members of the Society, but for those who are unfamiliar with it, a short review is provided on pages 124–126. Thirty-seven articles in the Journal of the Russell Society are referenced, and there are numerous photos of specimens found on field trips. Three such specimens, all found since the first part of the journal was produced in 1982, are shown on the facing page. A reminder that interesting specimens remain to be collected and documented across the British Isles. REFERENCES Greg, R.P. and Lettsom, W.G. (1858). Manual of the Mineralogy of Great Britain and Ireland. John van Voorst, London. Starkey, R.E. (2018). Minerals of the English Midlands. British Mineralogy Publications, Bromsgrove, Worcestershire, England. Tindle, A.G. (2008). Minerals of Britain and Ireland. Terra Publishing, Harpenden, England. David Green and Malcolm Southwood, Journal Editors ERRATUM Ince, F. (2017). A review of the minerals associated with the igneous rocks of southwest Leicestershire. Journal of the Russell Society, 20, 3–29. On page 25, the final sentence of the quotation describing the Miller Indices for some quartz crystals should read: “Of 52 crystals examined, 43 showed the development of the left trigonal pyramid {2111}, and rarely the left trigonal trapezohedron {6151}.”, (not 6111). 2 Journal of the Russell Society (2018) Above: A brown sphalerite crystal (7 mm across) on calcite with chalcopyrite; Level G, West Face, Cloud Hill Quarry, Breedon on the Hill, Leicestershire; 35×30×15 mm; Frank Ince Collection (FI-2447). Figure 495, Minerals of the English Minerals, p. 207. Right: Intergrown white to pink, tubular, pseudostalactitic masses of baryte (the enclosing brown calcite matrix has been removed using dilute hydrochloric