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The Geologists' Association

@geolassoc.bsky.social

Founded in 1858, the Geologists' Association (GA) is a charitable organization that exists for all geologists and earth scientists. Our offices are co-located with those of the Geological Society at Burlington House in central London.

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The Geologists' Association @geolassoc.bsky.social · 2d ago

Welcome to September with a dramatic image from the 2026 Geologists' Association calendar of the view from the Jungfrau towards the Aletsch Glacier in Switzerland taken by Graham Hickman.

The Geologists' Association @geolassoc.bsky.social · last wk.

There are just a few days left to submit up to 3 photos to our 2026 Geology Photographic Competition. 💰 Cash prizes! 📸Free to enter 📸 Open to GA members and non-members ⏰Deadline: Friday 28th August 2026 Full details on our website: geologistsassociation.org.uk/photocomp_en...

The Geologists' Association @geolassoc.bsky.social · 2w ago

A Lower Cretaceous oyster reef (Cinder Member, Purbeck Limestone Group, Dorset, southern England): biotic response to co-seismic sea-level rise? by Jonathan D. Radley & Robert A. Coram In Proceedings of the Geologists' Association, vol 137, issue 4. Read online www.sciencedirect.com/.../pii/S001...

Measured sections through the Cinder Member (Durlston Formation, Purbeck Limestone Group) in south Dorset, southern England, demonstrating facies associations. a, b, and c = divisions recognised by Ensom (1985a) for Worbarrow Tout and Clements (1993) for Durlston Bay.

Details of Cinder Member (Durlston Formation; Purbeck Limestone Group), south Dorset, southern England. Hammer in a, b, f, and h is 29 cm in length; 28 cm in length in c, e, and g. (a) Burrows on undersurface, Stair Hole (NGR SY 822798). (b) Junction between Cherty Freshwater Member and basal Cinder Member (facies association 1), indicated by dashed line, Durlston Bay (NGR SZ 036784). (c) Probable scour in ‘Hard Cinder’ division (facies association 1), indicated by arrow, immediately to the right of the hammer head. Durlston Bay. (d) Facies association 2, Stair Hole. (e) Nested oysters, loose block, Durlston Bay. (f) Facies association 3 showing sediment-filled articulated oysters, Man o' War Cove (NGR SY 807802). (g) Facies association 4 (FA4) storm beds at top of Cinder Member, east side of Lulworth Cove (NGR SY 828797). (h) ‘Soft Cinder’ division, Durlston Bay (see Fig. 4), showing facies associations (FAs) present.

Northern margin of the Portland–Wight Basin (south Dorset, southern England) showing localities mentioned in the text and structural framework for the Purbeck Limestone Group. Incorporating data from Underhill (2002) and Gallois et al. (2018).

Early Cretaceous (Berriasian) palaeogeographical reconstruction (southern Britain) showing principal depocentres, and structures influencing deposition of the Purbeck Limestone Group. The Pewsey Basin, Mere Sub-basin and Portland–Wight Basin make up part of the composite Wessex Basin (see text). SCSB = Southern Celtic Sea Basin. WAT = Western Approaches Trough. WS = Wessex Shelf. RF = Ridgeway Fault. PF = Purbeck Fault. PI = Portsdown Inversion. WBF = Wight–Bray Fault. CECH = Central English Channel High. LPF = London Platform Faults. MWH = Market Weighton High.

Adapted from Cope et al. (1992), Hamblin et al. (1992), Hawkes et al. (1998), Underhill and Stoneley (1998), Underhill (2002) and Rawson (2006).

The Geologists' Association @geolassoc.bsky.social · 2w ago

Calling all Key Stage 2 Science teachers! Our SchoolRocks! Year 3 'Rocks & Soils' & Year 6 'Evolution' specimen boxes for the autumn term are booking up fast. Order yours now by emailing schoolrocks@geologistsassociation.org.uk Full details on our website: geologistsassociation.org.uk/schoolrocks

The Geologists' Association @geolassoc.bsky.social · 3w ago

Bartoncetus wanklyni, new genus of a small dorudontine whale from the Bartonian of England; a lost skull and a forgotten postcranial skeleton by Henk Jan van Vliet et al. In Proceedings of the Geologists' Association, volume 137, issue 4: www.sciencedirect.com/.../pii/S001...

Map of the western and southwestern parts of the European continent in the Bartonian, showing the locations, where remains of small dorudontine archaeocetes have been found. The North Sea Basin was connected with the Tethys and the later Paratethys Oceans through amongst others a south-eastern passage east of the Bohemian Massif, but was probably separated from the Atlantic Ocean by a land bridge between Normandy, France and Southwest England. Map based on Curry and Smith (1975), Smith and Curry (1975), Rögl (1999, fig. 1), Popov et al. (2004), Marandat et al. (2012), Gol’din and Zvonok (2013, fig. 1), Gibbard and Lewin (2014, figs 1–3), de Lapparent de Broin et al. (2018, fig. 1), and Lenz et al. (2021, fig. 1). H, region of Helmstedt, Germany; H-D B, Hampshire–Dieppe Basin, England; L, Lubartów, Poland; V, Italy: Varano, Italy.

Cervical vertebrae, vertebrae A–F (Ce2, Ce‘3’–‘5’, Ce6–7), ‘Zygorhiza’ wanklyni Seeley, 1876, BNSS0777, from the Bartonian of Barton-on-Sea, England. A1–3. Vertebra A (Ce2) in anterior (A1), in left lateral (A2) and in posterior (A3) view. B. Vertebra B (Ce‘3’) in anterior view. C. Vertebra C (Ce‘4’) in anterior view. D. Vertebra D (Ce‘5’) in anterior view. E. Vertebra E (Ce6) in anterior view. F. Vertebra F (Ce7) in anterior view. Ce‘3’–‘5’ in quotation marks, because the position is not completely certain. Scale bar is 50 mm.

Section of the early Eocene strata in Christchurch Bay, England and the distribution of dinocysts, as encountered in BNSS0777. A. Section of the Barton Clay Formation: stratigraphy of the Lutetian and Bartonian sediments in Christchurch Bay, England. Strata with finds of small dorudontine archaeocetes are indicated with braces. Modified after Hooker (1986, text-figure 2) and information from the British Geological Survey, Barton Clay Formation (https://webapps.bgs.ac.uk/lexicon/lexicon.cfm?pub=BAC). B. Section of the Barton Clay Formation correlated with age-diagnostic dinoflagellates in the sediments adhering to BNSS0777. Based on Bujak and Mudge (1994) (dinoflagellate cysts), Eldrett et al. (2004) (polarity zones), adjusted to the Geologic Time Scale 2020, Gradstein et al. (2020). Age of the Barton Clay Formation ranging from approximately midway Chron19r (41.4 Ma) to the earliest part of Chron17r (38.4 Ma) (King, 2016, fig. 72). Lut., Lutetian; Rup., Rupelian; A. dictyoplokum, Areosphaeridium dictyoplokum; A. fenestratum, Areosphaeridium fenestratum; A. michoudii, Areosphaeridium michoudii; H. porosa, Heteraulacacysta porosa; R. borussica, Rottnestia borussica; Rh. draco, Rhombodinium draco. Down-left elbow arrows indicate the last occurrence datum (LOD), and up-left elbow arrows indicate the first occurrence datum (FOD) of the dinocyst taxa.

Palaeoart reconstruction of the living Bartoncetus wanklyni (Seeley, 1876), gen. et comb. nov. by Jonas Hakkens.

The Geologists' Association @geolassoc.bsky.social · 3w ago

We are pleased to announce that Dr Lucia Pérez-Diaz will deliver one of the headline talks at the Festival of Geology this year: The Secret Ingredient for a Habitable Planet. Lucia will also be signing copies of her latest children's books: How the Oceans Work & How the Earth Works.

The Geologists' Association @geolassoc.bsky.social · 4w ago

There's still time to submit up to 3 photos to our 2026 Geology Photographic Competition. 💰 Cash prizes! 🆓 Free to enter 📸 Open to members and non-members ⏰Deadline: Friday 28th August 2026 ℹ geologistsassociation.org.uk/photocomp_en...

The Geologists' Association @geolassoc.bsky.social · 4w ago

'James Hutton and the Restless Earth' is an interesting documentary by Karine Polwart, Dave Milligan & Pippa Murphy, which weaves together the thoughts of Angus Millar, Professor David Farrier & Ilana Halperin plus music specially created for the programme ⏰19.15 BST Sunday 9th August, BBC Radio 4

The Geologists' Association @geolassoc.bsky.social · last mo.

Miocene vertebrate footprints from the Eastern Paratethys deposits of the southern Caspian, Northern Iran by Nasrollah Abbassi et al. In the latest edition of Proceedings of the Geologists' Association (PGA), vol 137, issue 4 Read online via Science Direct: www.sciencedirect.com/science/arti...

A–B. Photo and sketch of tri- to possibly tetradactyl imprints with an elongate sole impression with numerous bird footprints (Uvaichnites isp.).

Location map, vertebrate fossil tracksite located eastern flank of the Shahid Rajaei Dam, south Sari, Alborz Mountains.

A. Outcrops of Miocene sediments in the eastern side of the Shahid Rajaei Dam, arrow shows footprint bearing layer position, began by ridge-forming conglomerate. B–C. Bivalve fossil and invertebrate ichnofossil (Planolites isp.) in the sandy mudstone, lower part of studied section. D. Basal conglomerate and footprint layer outcrop, view eastwards. E. Stratigraphical column of Miocene sediments in the studied section, with position of vertebrate footprints (a–e).

Map of Paratethys basin with distribution of vertebrate footprint site around the eastern Paratethys (red numbers in circle): 1. Romania (Panin and Avram, 1962), 2. Ukraine (Vyalov, 1965), 3. Armenia (Bogachev, 1958), 4. Turkmenistan (Vyalov, 1983), and 5. Iran (this study); and out of eastern Paratethys (green numbers in square): 1. Hungary (Kordos, 1983), 2. Slovakia (Schmidt, 1965), 3. Austria (Thenius, 1967), 4. Turkey (Mesci et al., 2019), and 5–9. Iran (Abbassi, 2022; Abbassi et al., 2024; Abbassi and Amini, 2008).

The Geologists' Association @geolassoc.bsky.social · last mo.

Welcome to August 2026 with a colourful picture of The Great Opencast, Parys Mountain, Anglesey taken by Lydia Wardley, which is one of the images in our 2025 Photographic Competition.

The Geologists' Association @geolassoc.bsky.social · last mo.

We are pleased to announce that Professor Phil Manning, Director of Science at the Natural History Museum Abu Dhabi and Chair of Natural History at The University of Manchester will deliver one of the headline talks at the Festival of Geology this year: Impossible Fossils.

The Geologists' Association @geolassoc.bsky.social · last mo.

The latest edition of Earth Heritage magazine is out now! Issue 65 is full of interesting and informative articles about geology and earth-science sites and initiatives across the UK Free online: www.earthheritage.org.uk/.../EH-65_fi... Buy a hard copy: geologistsassociation.org.uk/earthheritage/

The Geologists' Association @geolassoc.bsky.social · last mo.

Thank you to Paul Hildreth of Yorkshire Geological Society for leading our weekend field meeting to Flamborough Head and the Yorkshire Coast. We enjoyed many opportunities to examine the strata up close, including an in-situ Sternotaxis plana zonal marker fossil. Photo credit: Cathy Gallagher.

Paul describing the chalk exposure to the assembled group. Photo: Cathy Gallagher.

Sternotaxis plana zonal marker fossil. Photo: Cathy Gallagher.

The Geologists' Association @geolassoc.bsky.social · 2mo ago

We currently have a vacancy for an Honorary General Secretary. If you think you have the experience and skills necessary to fulfil the role and would like to apply for this position, please contact the GA President: president@geologistsassociation.org.uk

The Geologists' Association @geolassoc.bsky.social · 2mo ago

Save the date! Join us and our colleagues from @rockwatch.bsky.social on Saturday 7th November 2026 from 10.30am - 4.30pm at Burlington House in London for our FREE Festival of Geology. Full details coming soon via our website: geologistsassociation.org.uk/festival/

The Geologists' Association @geolassoc.bsky.social · 2mo ago

Booking for the GA 2026 Conference in York is now open! 🗓️25 - 27 September 2026 📍York Join us for for the whole weekend or just one day - you choose. 🥳GA Student Members can attend the Saturday Conference for FREE! ℹ️ Full details on our website: geologistsassociation.org.uk/conferences/

The Geologists' Association @geolassoc.bsky.social · 2mo ago

Our field excursion to the White Cliffs of Kingsgate, which sadly had to be cancelled on Saturday 6th June, has been rearranged and will take place on Saturday 17th October Cost: £5 GA Members / £15 non-members For full details see our website: geologistsassociation.org.uk/ukfield/#kin...

The Geologists' Association @geolassoc.bsky.social · 2mo ago

Thank you to Dr Cathy Hollis for leading an informative field meeting to examine the Visean strata around the Great Orme headland. The group were treated to many examples of Late Carboniferous exposures, illustrating the growth and demise of the Mississippian carbonate platform.

Cathy preparing to describe the Pier Dolomite exposure to the group.

The Geologists' Association @geolassoc.bsky.social · 2mo ago

Volume 25, number 2 (June 2026) of the Geologists' Association Magazine is out now! This issue includes articles on trips to Iceland and New Zealand, an update on the Mary Anning statue maquette road trip, 2026 GA Award winners and the 2025 Halstead Lecture to name but a few.

Front cover of the Geologists' Association quarterly magazine, volume 25, number 2 (June 2026) showing a picture of the western Southern Alps shrouded in dense forest and almost permanent cloud, looking toward the Cropp River basin and Hokitika Gorge. Aotearoa, the Maori name for New Zealand, means 'long white cloud'. Photo: Jonathan Turner.

Ellie Kew as Mary Anning at Somerset Earth Science Centre, which is also hosting the Mary Anning statue macquette.

New Zealand plate boundaries configuration and a schematic cross-section through the Southern Alps, The deep geometry of the Alpine Fault is speculative. Adapted from Little et al. (2005).

The Geologists' Association @geolassoc.bsky.social · 2mo ago

Welcome to July with a spectacular image of Serpentine boulders, Kynance Cove, Cornwall from the Geologists' Association 2026 calendar, which was taken by Jonathan Turner and won second prize in the GA 2025 Photographic Competition.

The Geologists' Association @geolassoc.bsky.social · 2mo ago

Thank you to Emma Nicholls & Duncan Murdock of @morethanadodo.bsky.social and Mark Stanway, Quarry Manager at Dewars Farm Quarry operated by Smiths Bletchington for hosting the Geologists' Association President's Day visit yesterday.

The Geologists' Association @geolassoc.bsky.social · 2mo ago

Join us online on Friday 3rd July 2026 at 19.00 BST for our next free talk - All fossils are rotten: the science of death, decay, and soft tissue preservation by Thomas Clements The talk will be via Zoom. Non-members should call 020 7434 9298 or email sarah@geologistsassociation.org.uk for details

The Geologists' Association @geolassoc.bsky.social · 2mo ago

Congratulations to Dr Colin Prosser on being appointed MBE in the King's Birthday Honours list 2026 in recognition of his services to geoconservation at Natural England Colin is the GA Geoconservation Officer, is actively involved in the PGA publications committee and is also a former GA President

The Geologists' Association @geolassoc.bsky.social · 3mo ago

A second specimen of the enigmatic Wealden reptile Yaverlandia by Darren Naish & Steven C. Sweetman. In Proceedings of the Geologists' Association, volume 137, issue 3. Available now via Science Direct: www.sciencedirect.com/science/arti...

Yaverlandia bitholus Galton, 1971. Holotype specimen, MIWG 1530, in dorsal view (A) and ventral view (B). IWCMS. 2012.585 in dorsal view (C), anterior view (D) and ventral view (E).

Schematic lithological log of the upper part of the Wessex Formation exposed in the cliff and on the foreshore in the vicinity of Yaverland on the south-east coast of the Isle of Wight. Modified from Sweetman et al. (2015). Bed numbers from Radley (1994).

Outline map of southern Britain showing the location of the Isle of Wight (A). Outline geological map of the Isle of Wight showing the locality from which the holotype specimen MIWG 1530 and the second specimen, IWCMS. 2012.585, were recovered (B).

Cover of the scientific journal Proceedings of the Geologists' Association.

The Geologists' Association @geolassoc.bsky.social · 3mo ago

Join us & @rockwatch.bsky.social on 13-14 June at Lyme Regis Fossil Festival for a weekend full of family-friendly fossil-related fun. Look out for our stand in the Lister Gardens Marquee. Plus, Ben Cunningham, one of our Student Representatives, will be giving a free talk at the Driftwood Cafe.

The Geologists' Association @geolassoc.bsky.social · 3mo ago

There's still time to register for our next free online lecture, tomorrow evening (Friday 5th June) at 19.00 GMT: Trace fossils: footprints and burrows - evidence of life when there are no bones, teeth, shells etc with Maurice Tucker. Email sarah@geologistsassociation.org.uk to register.

The Geologists' Association@geolassoc.bsky.social · 3mo ago

Join us for our next evening talk: Trace Fossils: footprints and burrows - evidence of life when there are no teeth, bones etc by Maurice Tucker, University of Bristol. 📅Friday 5th June, 2026 🕖19.00 BST 📍Online via Zoom 🎟️Free

The Geologists' Association @geolassoc.bsky.social · 3mo ago

Welcome to June with a mesmerising image taken from the Geologists' Association 2026 calendar of the Isle of Staffa, Inner Hebrides, Scotland taken by Peter Lincoln.

ISLE OF STAFFA, INNER HEBRIDES, SCOTLAND

The island of Staffa, with its famous Fingal’s Cave, is entirely of volcanic origin. It consists of black, fine-grained basalt lava from volcanoes active in the Eocene epoch. The slow cooling of one of the lava flows has resulted in the formation of remarkable polygonal columns.
Photograph: Peter Lincoln.

The Geologists' Association @geolassoc.bsky.social · 3mo ago

Come and join us at the Great Exhibition Road Festival on the 6th & 7th June 2026. The GA stand will be there both days with our interactive exhibits, fossil & rock specimens and information so do call by and say hello! Full details on their website: www.greatexhibitionroadfestival.co.uk

The Geologists' Association @geolassoc.bsky.social · 3mo ago

Carboniferous tetrapod fauna of the fossil lycopsid trees at Joggins and the origin of the hollow tree guild by John H. Calder, Andrew C. Scott, Brian L. Hebert, Andrew C. Milner & Matthew R. Stimson. In Proceedings of the Geologists' Association, vol 137 (2): www.sciencedirect.com/science/arti...

Plate of representative tree fauna: (a) characteristic assemblage of tetrapod bones and charcoal; (b) jaw of the non-amniote Hylerpeton dawsoni (R4180); (c) coprolitic mass and bones of the amniote Hylonomus lyelli (R4564); (d) the early land snail Dendropupa vetusta (G92); (e) detail of coprolitic mass in (c); (f) two specimens of the millipede Xyloiulus sigillariae (28795). Photographs (b–f) courtesy Natural History Museum, London.

Modern and ancient fire scars: (a) basal fire scar in Taxodium distichum, inhabited by nine-banded armadillo (Dasypus novermcinctus), Mississippi Delta; (b) notched, charred lycopsid tree base rife in tetrapod skeletal material, below coal 21 of Logan (1845), interpreted as a fire scar; (c) interpretive drawing of tree and fire scar in (b). Key to interpretive drawing: a) massive sandstone; b) silty fine charcoal with tetrapod bones; c) coalified strands of cortex/periderm; d) silty sandstone infilling fire scar; e) massive sandstone encircling tree.

The excavated tree-fill at site R114, Rusinga, Kenya, that bore the skeletal remains of Proconsul africanus (Mark Teaford photograph, used by permission). b) Depiction of the ‘1951’ Proconsul-bearing tree from the Miocene of Kenya, from Walker and Teaford (1989), used by permission (illustration by Tom Prentiss, 1936–1997).

Location map of fossil tree fauna sites at Joggins. Meterage refers to stratigraphical section of Davies and Gibling, 2003 (see Fig. 2).

The Geologists' Association @geolassoc.bsky.social · 3mo ago