Hartwell House visit with Mike Howgate for the Buckinghamshire Geology Group
Saturday 25th June 2022
The happy group in the the grounds of Hartwell House…..
Titanites sp. ammonite from the Bucks Portland Stone strata, at least 30cm diameter.
The first of many Lower Greensand bowel-stones laying on the edge of the path.
Mammillated shaped bowel-stone, all from the local Whitchurch Sand bed.
Buckinghamshire pudding stone from local Bradenham.
More Bradenhan puddingstone.
Pudding stone blocks in the rag-stone external walls.
A large Titanites sp. ammonite in the boundary wall
A beautiful room in the house which served as our lunchtime eating area.
An attractive bridge in the grounds which was once the central span of old Kew Bridge. The large lake is fed from a spring just to the left of the picture.
A large piece of bowel-stone buried in the wall.
Mike Howgate showing off the bowel-stone and local flint wall decoration.
The limestone ‘Egyptian Well’ just outside the boundary wall with its own water supply and carved hieroglyphics.
Part of the boundary wall built and dated 1857 using flint and Peterhead granite.
A 2.5mt basalt column in a courtyard. Not a local stone! Origin unknown……..
Buckinghamshire County Resources Centre Museum – a few examples of fossils and minerals from the Dr. John Lee collection who at one time owned Hartwell House.
All photographs taken by Richard Furminger AGS and ‘Copyright Discover Bucks Museum’.
Bivalve fossil – Lima hartwelliana.
Pinna sp. – a marine bivalve or pen shell. From the Hartwell Kimmeridge clay.
Pleurotomaria sp. gastropods from the lower Portland pebble bed, Hartwell.
Jurassic ammonites Dactylioceras communis and Dactylioceras tenuicostatum from Whitby, Yorkshire.
Tourmaline in quartz from Sweden.
Fluorite pale-lavender cubes partly encrusted with quartz. Weardale, Co. Durham.
Calcite from Portland stone quarry.
Fossil fish Dapedium politum from Loughborough, Leicester.
A small partial skull of an Ichthyosaur from the lias, Jurassic, Nottinghamshire.
Coprolite nodules collected from the shoreline of Leith, by Richard Bull.
The red pebbles are loose coprolitic nodules eroded out of the Wardie section.
All the above photos are the property and copyright of the Lyme Regis Museum.
Thanks to Richard Bull BSc for all the information.
Photographs from the Harrow & Hillingdon Geological Society ‘Rock Show’ which was held 12th – 28th February 2020 at Uxbridge library. The three large ammonites below (15″ to 17″ across) are from the show and are from the collection of Bob Maurer of the H&HGS with his permission. Bob is a regular speaker to the AGS and also an exhibitor at our annual Mineral, Gem & Fossil Show.
The exhibition is well worth a visit with cabinets and tables full of interesting labelled rocks, fossils and minerals. See the Harrow & Hillingdon Geological Society website for the exact February date.
Photo RSF.
Tropaeum bowerbanki (open coiled Hetromorph)
Lower Cretaceous 100 – 115 million years ago. From the Lower Greensand Ferruginous Band, Crioceras Bed, Atherfield, Isle of Wight. Evolved from an open coiled form in the Jurassic era to a closed coiled form in the cretaceous era.
Photo RSF.
Australiceras gigas, open coiled Hetromorph. Cretaceous era, 90 – 120 million years ago. Whale Chine, Isle of Wight.
Photo RSF.
Australiceras gigas, an open coiled Hetromorph. Cretaceous era, 90 – 120 million years ago. Whale Chine, Isle of Wight.
Uxbridge Underground station, Metropolitan & Piccadilly lines, with carvings in Portland stone, a freestone, depicting railway wheels and carriage springs. Built in 1938 in an Art Deco/Modernism style there is some wonderful stained glass inside.
Just down the road from the station is ‘The Chimes”, or ‘Intu Uxbridge’, a large shopping centre with some wonderful polished limestone floors on the lower ground. They are covered in belemnites and ammonites, almost too good to walk on. Part of the phragmocone, or flotation chamber of some belemnites is preserved in many cases. In addition, the septa or chamber walls of the ammonites are also very obvious in many of the examples. The floor is Solenhofen limestone from Germany, Jurassic, 180 million years old.
All photos RSF.
‘First Animals’ – an exhibition at the Oxford University Museum of Natural History.
Friday 14th February 2020.
Led by Mike Howgate Msc. FLS.
The exhibition contained fossils from the Sirius Passet fossil site in Greenland (G), the Chengjiang fossil site in the Yunnan province China (C) and were loaned from YKLP, Yunnan University, China, and from the Museum’s own collection (OM).
Text explanations courtesy of the Oxford Museum and photographs by RSF of the AGS.
The impressive Oxford University Museum of Natural History. The facade is Bath Stone with detailing in Red Bristol sandstone and Hornton Ironstone.
Charnia masoni, (cast) Charnwood Forest, Leicestershire, UK. 562 – 557mya. This specimen of Charnia was found in 1957 in Pre-Cambrian rocks. It is still one of the best preserved examples ever discovered, showing the four levels of branches-of-branches that characterise the species. (OM)
Charnia masoni, (cast) Charnwood Forest, UK. Pre Cambrian, 562-557mya. Such large Charnia examples are extremely rare, and this is one of the two largest at 65 cm long. It is incomplete, so the original animal may have been over a metre long. (OM)
Misszhouia longicaudata, Yunnanprovince, China. Cambrian. Unlike trilobites, Misszhouia had no hard skeleton, but it does show exceptional preservation of soft tissues. The dark stripe running down the middle of the specimen is its gut, while the fine ridges on the head and body reveal the rare evidence of its delicate legs. (C)
Halkieria evangelista is a Cambrian mollusc with a long slug-like body protected from predators by hundreds of overlapping plates called sclerites, and a large plate at either end. The creature may have had a muscular foot and mouthparts, which allowed it to move slowly over the sediment, grazing on bacterial films. (G)
Wiwaxia is known from fossils of the toughened scales on its back, as well as rare soft tissues, including a slug-like foot underneath. It is though to be a relation of modern molluscs. Cambrian. (photo of poster)
Amplectobelua symbrachiata. Early Cambrian. One of the largest Chengjiang animals, Amplectobelua was a top predator that used wide body flaps to swim above the sea floor, with large stalked eyes used to spot prey. This specimen shows the two spiny appendages on the front of its head that helped it to grasp and hold prey, before the three pairs of shorter tooth-like appendages shredded food as it was passed towards the mouth opening. (C)
Eoredlichia intermedia was a trilobite that lived on the sediment surface, feeding by scavenging decaying organisms and using paired legs to walk over the sea floor. The pair of long antenna at the front end of the head was used for sensing its surroundings and finding food. The hard body segments protected the legs, gills and soft body of the trilobite from predators. Middle Cambrian (C)
Cricocosmia jinningensis had a distinctive snout called a pharynx, covered in spiny tooth-like structures. The pharynx could be retracted into the spiny proboscis or turned outwards to capture prey. Cricocosmia was a predator that buried itself in the sea-floor sediment during Cambrian times and fed on slow-moving animals that it ambushed from its burrow. (C)
Ogygopsis klotzi was very abundant in the Burgess Shale. It was a very large trilobite that would have scoured the sediment for food. Middle Cambrian. (OM)
Cinderella eucalla is a genus of trilobite-like Cambrian arthropod. It lived less than 50 million years after Dickinsonia, following the extraordinary diversification of animal life called the Cambrian explosion. Animals now dominated the planet and had already evolved all the body plans that we see today. (C)
A selection of other items from the visit to the museum………
Fault rock from North Cornwall. Interbedded siltstone and dolomite with Chert nodules. The specimen is cut by two minor faults and the central part has moved up relative to the two sides.
Fault breccia. The dark casts are metagreywacke, in a matrix of calcite.
Porphyritic amygdaloidal basalt, Castleton, Derbyshire. This rock is both porphyritic, with large feldspar crystals in the brownish matrix, and amygdaloidal, with round gas-bubble holes that have been filed with silica.
Diorite from Germany. Diorite consists of a white mineral, plagioclase feldspar and a black mineral, hornblende. In other diorites the hornblende may be replaced by biotite mica.
Bioclastic limestone with bivalve and gastropod fragments.
Porphyritic granite or Shap granite from Shap, Cumbria. In certain igneous rocks some mineral grains may be larger than average, such as the pink feldspars in this rock. The large grains are known as phenocrysts, and the rock is said to be porphyritic.
Granite with basic xenoliths. Intruding granitic magma may pluck off pieces of the native rock through which it is intruding. These dark, rounded inclusions are known as xenoliths.
A Crinoid, Encrinus liliiformis, Lamarck, Germany.
Dinosaur eggs, Cretaceous period. 145 – 66 mya. Laid by a long-necked sauropod dinosaur in what is now China.
Fossil Dinosaur skin, Cretaceous period, 145 – 66mya. Hell Creek formation, South Dakota, USA. Found near the skeleton of an Edmontosaurus, a large herbivore.
Fossil fish, Notogoneus osculus, Eocene, Wyoming, USA.
Impactites and Shock Metamorphism.
A behind-the-scenes visit to the Natural History Museum.
With John Wong December 2019.
All photos RSF (Some behind glass)
Natural History Museum winter scene.
Suevite from Germany. A breccia with glass and lithic fragments. NHM Reg. No. 1964, 583.
Coesite from the Barringer Crater, Arizona. NHM Reg. No. 1962, 4.
Impactite from Waber, Saudi Arabia. Impact melt breccia. NHM Reg. No. 202, M13.
Canary Wharf Station. Not a very beautiful station, but, check out the huge Solenhofen limestone wall from Germany, and the Red Granite seating from Brazil. Designed to impress!
Too good to sit on…..
Travelling Belemnites in the Solenhofen Limestone……..
Detailed Ammonite with the chambers clearly outlined.
Belemnite rostrum or guard clearly showing the alveolus.
Fior di Pesco Italian marble.
Marble mosaic floor by Emma Biggs.
A lifelike figure in the rain….No, not an AGS member but a statue, ‘Seated Man’ by Sean Henry 2011. His feet are firmly planted on Migmatite paving from Brazil. In the background a Swedish Granite fountain.
Ohio Sandstone
Liesegang banding and iron staining.
Mike pointing out the banded Gneiss.
The Swedish granite fountain.
With Xenoliths…….
Solenhofen limestone columns with orbicular granite pedestals.
Close up of the intricate carving.
Close up of the orbicular granite. Formed by crystallisation from a fluid rich supercooled dioritic magma around a seed crystal nucleus.
Amongst the building stones a bronze statue, ‘Returning to Embrace’ by John Buck, 1999.
A damp but happy bunch after a very informative and interesting walk.
Essex Jam, a Monastery, an Earthquake and a Zeppelin…….
A walk with Mike Howgate 10th August 2019
All photos RSF – AGS
St. Michael and All Angels, Copford, Essex. Dates back to the 1130’s.
Mike explaining the mixed building stones: Re-used Roman bricks, ‘False Pudding Stone’, Flint, Ferricrete and Kentish Ragstone.
Modern pointing almost obliterating the the stones and brick work.
The 12th century Norman rounded apse with Victorian stained glass and re-use of Roman bricks or tiles.
Blocked Norman doorway.
Gothic style archway added during restoration.
‘Christ in Glory’ in the apse, surrounded by angels and apostles. Restored Medieval art.
Next, a more unusual place of worship….
An Orthodox Monastery in Tolleshunt Knights, Essex with incredible mosaics.
Slate and ceramic mosaic.
Our tour guide, a Nun from the monastery.
An impressive and huge outdoor mosaic built by the inhabitants, one of many around the site.
The interior was adorned with some beautiful paintings, or frescoes.
Next stop, world famous jam makers ‘Wilkins’ factory museum in Tiptree and some of their antique equipment…….A fruit press, bronze mixing bowl and a French cherry stoner!
Followed by…….
14th century Church of St. Stephen, Great Wigborough. Damaged during the great earthquake of 1884 and extensively restored. Walls built from rubble, ragstone and septaria with limestone dressings.
Rubble in the exterior walls.
– and Basalt.
Inside the Church, photographs and a piece of the crashed Zeppelin L33 which came down nearby in 1916.
Last stop of the day………
The damaged 15th century pub…
The cracked plaque says it all……..
Terracotta panels and figures from inside the natural History Museum, London.
All photos RSF.
Some beautiful minerals from the Natural History Museum, London.
All photos RSF.
More than a few pictures of a fascinating walk through the city looking at building stones on Thursday 14 June 2018: Stones of the City (2) with Mike Howgate MSc.
Travertine from N.E. Rome, a limestone, formed by precipitation. Used extensively by the Romans.
Travertine turned column.
York Stone pavement with Liesegang rings.
More York Stone machined with ‘bumps’ to give warning of a kerb for the partially sighted.
Black Basalt statues by Xavier Corbero. There is somebody in there!
Rough hewn sandstone with dune bedding. Exchange Square, Liverpool St. Station.
Orbicular granite with xenolith piece.
Mica Schist slabs to walk on………
Water feature at Liverpool St. Station.
Patinated bronze on granite plinth. ‘Broadgate Venous’ by Fernando Botero.
Pentelic Marble war memorial inside the station.
Pentelic Marble close up. From Mount Pentelicus quarries north of Athens.
Detail of Portland oolitic limestone columns inside the station.
Entrance to T.M.Lewin, Jermyn St. Unusual Gypsum construction, with brown hematite iron colour. A little worn and knocked about but Mikes favourite.
Some Portland Stone fossils, 3mm – 4mm proud due to acid rain and erosion. Finsbury Circus.
Dartmoor granite with large crystals of plagioclase feldspar.
Banded Gneiss with garnets.
Marble cladding of unknown origin.
‘Faceted Column’ by Stephen Cox R.A. 1999. Chiswell St. Finsbury Square. EC1. Dolerite from Whin Sill, Northumberland.
Sore feet but a happy and educational few hours!
All photos Richard Furminger AGS.
A few pictures from the joint field excursion with the Kirkaldy Society and Geo-Suffolk to the Ipswich Museum and the Suffolk Crags led by Bob Markham. 16th – 17th June 2018
Thanks to Mike Howgate for the pictures and captions.
The Group outside the Ipswich Museum.
Whale ear bone from the coprolite bed at the base of the Red Crag.
Mammoth tooth grinding surface.
Sharks teeth display with large but worn Miocene Carcharodon Megalodonon teeth from the coprolite bed.
Your Chairman and others on Coprolite Street.
Cross bedded Red Crag in ‘Bullock Pit’ at Rockhall Wood SSSI.
Display board explanation of the ‘Coralline Crag’ island in a ‘Red Crag’ sea.
The ten-year-old replanted ‘Pliocene Forest’.
‘Pliocene Forest’ display board.
35cm diameter x 2cm ‘Stepping Stones’ photographed in a U.K. garden centre. Too nice to walk on. Some Liesegang rings (?) and iron staining give a wonderful multicoloured appearance. These sandstone slabs possibly come from Bari Nagour, Rajasthan, India. It is named ‘Teak and Rainbow’. Watch the slide show……
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Photographs from an AGS visit to Sedgwick Museum, Cambridge with Mike Howgate 23rd March 2018.
The Sedgwick Museum, Downing Street Cambridge. Limestone Iguanodon & Megatherium.
Ammonite Arietites OLecostephanus
Hamites maximus – from Gault Clay, Folkestone Kent.
Close up of ammonite Cosmocerus – Gulielmi. Oxford Clay, Chippenham, Wiltshire.
Fossil bivalve mollusks – Trigonia
North American Mastodon tooth.
Starfish Astropecten.
Fossil Ferns & Tree Bark.
Jurassic Echinoids with spines.
Mosasaurus Camperi jaw – Maestricht Upper Chalk
Ichthyosaurus jaw – Whitby
Handsome fossil fish – Dapedius
Some of the happy AGS field trip members with Mike Howgate.
A great portrait of Adam Sedgwick.
All photos by RSF with permission of the museum. Through glass cabinet doors mainly with some editing……
Some very nice photos from AGS member Sue Jacobs taken while in Anglesey last year on a ‘Down to Earth’ magazine field trip.
Powys Mountain, once the largest copper mine in the world.
South Stack lighthouse, Holyhead, Anglesey.
Newborough beach with iron rich pinky Jasper.
OXFORD UNIVERSITY MUSEUM
A cast of the ‘Berlin specimen’ Archaeopteryx lithographica . Late Jurassic (152-146my), Solnhofen Limestone . Photo RSF
Two photographs from long time AGS member Gabriel Hodes:
An ammonite ‘Asterocerus confusum’ from Lyme Regis,
Lower Lias, Lower Jurassic site and found by Gabriel.
Lower Cretaceous Ichthyosaur vertebrae and some rib bones.
Found by Gabriel at Heath and Reach, Beds. on an AGS field trip!
Photographs from-
‘More Hertfordshire Churches‘ a walk with Mike Howgate, Friday 6th October.
Four Churches to be exact, a large octagonal dovecote, the Walkern Art Gallery, the Brewery Tea Rooms for lunch and a historical Motte and Bailey site in Pirton from 1139 AD.
All photos R.F.
Mike and group entering ‘St.Michael and all Angels’ at Waterford.
Some magnificent stained glass, this one by Karl Parsons 1929.
……and another by William Morris.
A plaque with ‘Memento Mori’ or ‘remember you will die’ symbols. A skull; wilted flowers; hour glass with time running out; the ‘thread of life’ with some threatening shears and others. Mike explained the meaning behind these morbid but fascinating Victorian images. ‘St. Mary & St. Thomas Church’.
Another plaque with ‘Memento Mori’ relating to a local family. St. Mary & St. Thomas Church.
Locally sourced flint wall with sandstone repairs to the windows. ‘St. Mary the Virgin’, Walkern.
Purbeck Marble effigy of a knight in a suit of chain armour with the visor drawn down c1200 AD. The fantastic carving is of William De Lanvalei of Walkern.
Another example of incredible stained glass, ‘St. Mary the Virgin’, Walkern.
A local ammonite, Ragstone, white Clunch or Totternhoe stone plus odd bits of Lower Greensand and even pebbles used in the construction of ‘St. Mary the Virgin’ in Pirton.
‘St. Mary the Virgin’ in Pirton.
Thank you to Mike Howgate for the photos and captions below: Mike organised the Teesdale trip of July for the AGS and the Kirkaldy Society. Their leader was Brian Young, formerly with the British Geological Survey.
‘Low Force’ with kayaks for scale
The group inspecting a huge xenolith within the Whin Sill
The Whin Sill at High Force
Leader Brian Young explaining where we are geologically…………
Water wheel erected at a lead mining museum
Large Carboniferous Sigillaria tree stump in Stanhope churchyard
Polished piece of Frosterly Marble (fossil coral Dibunophyllum)
John C………… being supported by a block of Frosterly marble
Penny and Sheila dying to get home and put their feet up……..
More geological photos from anywhere and everywhere…..
90cm (3ft) tall ‘Luton Puddingstone’. It stood for centuries on the corner of Market Hill in Luton protecting the corner of an adjoining building. At one time it was painted blue, eventually moved to a museum from where it was stolen, then later recovered. Now at Stockwood Discovery Centre, Luton.
Close up of the flint pebbles forming the conglomerate.
A large polished Porphyry Granite bench in Stockwood Discovery Centre gardens.
A mass of Feldspar phenocrysts.
All photographs R.F.
Basalt Columns at Reynisfjara “Black’ Beach, South Iceland.
Blue Lagoon, Grindavikurbaer, SW Iceland.
Retreating Solheimajokull Glacier, SE Iceland.
Close up of ash stained Solheimajokull Glacier.
‘Geysir’ geyser, Blaskogabyggo, South West Iceland.
Bubbling hot springs in the Haukadalur Valley, Blaskogabyggo, SW Iceland.
Gullfoss Falls, Hvita River, SW Iceland (people for scale).
View across the Thingvellir rift valley, between the North American and Eurasian Plates.
All pictures RF.
Mike Howgate’s ‘walk’ on Thursday 6th April 2017 –
‘The Pulhamite Industry’ in Hertfordshire’.
Restored Brick Kiln
Clay Puddling Wheel
Pulhamite is an artificial stone which was produced at a site near Broxbourne station from the 1830’s to the 1930’s. It was used in the manufacture of rockeries, fernaries, grottos and landscape features some of which look remarkably geological. We met up at a cafe alongside the river Lea then went to see the remains of the works, a kiln and bug wheel. After lunch we visited the Lowewood Museum to see their exhibition on the Pulhamite industry, which is on until the 28th. of April then it was on to the High Leigh Conference Centre to examine a Pulhamite ‘Millstone Grit’ gorge.
Pulhamite ‘Millstone Grit’ gorge and a happy group above enjoying Mike’s ‘Walk’. Thank you to Mike for the photographs.
Iron Meteorite
Gibeon Iron Meteorite. 132mm long and 2.8 kilos in weight and an iron-nickel alloy. From the famous Gibeon impact site in Namibia, West Africa.
Another view…A number of huge pieces from the same meteor are on show in Windhoek, capital of Namibia. Many thanks to C.D. for allowing me to photograph this piece.
Southbank Foreshore walk with John Wong + some hardy AGS members 2nd March 2017
Foreshore and St.Pauls + Millennium Bridge.
Not sure what we will find but one never knows……
Looks like flint, bricks, debris, chalk, limestone, granite, pebbles, sand….
This is the group that braved the cold and had a great day.
This is Diana’s best find. A piece of Acropora coral, very nice!
These are some of the other finds: animal teeth; animal bones; a marine shackle; c17th clay pipe bowl +stems (lots); chalk, boat nail, coal with fossilised wood; flint burrow cast; shells; pottery; glass; an acorn cupule or cap.
Clay pipe items found on the foreshore and how the pipes would have looked. Thank you to John Cook for the photo.
This is just a small amount of the interesting artefacts and even fossils that were found. Flint from being used as ballast in the past, as well as an old building material. Chalk from the ‘barge beds’ that were laid down on the shore for the flat bottomed barges to settle on when the tide was out. Large amounts of animal bones from restaurants and suchlike alongside the river in the past. Countless pipe stems and bowls from smokers past. A small bowl from the days when tobacco was much more expensive, larger bowls from more recently. Countless pieces of pottery, plain, decorated, glazed. Numerous pieces of iron work and steel from old boats broken up on the Thames shore. Coal from the loading wharfs that were scattered along the Thames. Lots of sand that had been deposited onto the shore for the 1951 Festival of Britain. Oyster shells, remains from an old fashioned meal. Tons of brickwork and stones from the Blitz and old wharfs and buildings that have gone to the Thames…..and a suspected Septarian Nodule or Concretion.
More photographs of the remaining part of the day……
Two sandstone paving slabs on Blackfriars Bridge, showing Liesegang rings.
Waterloo or ‘Ladies’ Bridge. Large structural pillar built of Calcarenite current bedded Portland limestone with numerous oyster shell fragments and ….
…reef building algae Solenopora portlandica showing growth rings. Sometimes said to resemble cauliflower florets.
Flooring in the Southbank Centre. Carboniferous Derbydene crinoidal limestone. Too nice to walk on….
Styolites have dissolved away an area of the crinoid fossils.
Bronze statue of Mandela mounted on a medium grained Gabbro plinth, 2 billion years old known as ‘Belfast Black’ from Mpumalanga S.A.
-near Victoria Embankment Gardens.
All Saints Church Fulham. The original 96ft. tower built of Kentish Ragstone around 1440.
Age and pollution taking its toll on the Cretaceous limestone.
Fulham Palace with diaper brickwork.
John C. looking very comfortable in the ‘Bishops Tree’- Fulham Palace.
London Sights
Sculptured and polished pavement rock at Millbank, SW1
Large carved Gypsum Alabaster figures – Jacob and the Angel. Tate Britain, Millbank. Jacob Epstein 1940-1.
Close-up: Angel supporting Jacob who has just collapsed…..
CRYSTAL PALACE DINOSAURS
Plesiosaurus + Ichthyosaurus – Jurassic
Teleosaurus – Triassic to Cretaceous
Teleosaurus + Plesiosaurus + intruders
Megalosaurus – Jurassic
Iguanodon, with nose spike – Cretaceous
Iguanodon close up
Section of ‘Geological Strata’ with simulated Carboniferous Limestone + Sandstone + Ironstone bands with faults and coal seam. Photos RF
AGS Field Trip led by John Wong to Bardon Hill Quarry, Leicestershire.
29th October 2016
This was the view down into the quarry. Fortunately a mini bus was available……..
Then the mist rolled in……but cleared almost immediately.
Dacite on the way down………
Andesite Breccia showing water-laid sedimentary structures. The steps or ‘Benches’ surrounding the quarry can clearly be seen.
Drilling machine for explosive charges.
Giant geological bucket for samples…….figure in background for comparison.
Quartz vein in the form of a boudinage structure in andesitic volcanoclastic sediment.
Light grey, fine-grained, graded and laminated marine sediment.
In the upper background, Triassic Mercia Mudstone deposits fill a paleo-valley, which is a Triassic unconformity on Precambrian Bradgate Formation volcanoclastic rock.
A fantastic day at an end……..
Some samples from the quarry:
Pictures by RF
Thank you AGS member Penny Badham for sharing some of her collection below:
Serpentine Chameleon – carved by Emmy Frester c.1960.
Flint nodule-Collected 1971 in Potters Bar garden. 1065grms. Polished by Frank Stokes.
Nummulites from Oman. Collected from building aggregate – 2009.
Polished examples of: 666-Gneiss 876-Clastic Rock 1076-Rhyolite 403-Breccia 498-Schist 661-Serpentine 694-Phyllite 692-Porphoritic Rock 1661-Olivine Gabbro – by Frank Stokes.
Chess Set – Gypsum, Serpentine and Mudstone. Carved + polished by Frank Stokes.
Pictures by R.F.
Three fantastic AGS field trips pictured below, make sure you go on the next one!
Mike’s ‘Bucks Geology and Churches trip # 2’
Casts and moulds of bivalves in Portland Stone in Dinton Church, Bucks. (Mike Howgate)
Dragons and the Tympanum of Dinton Church. (Mike Howgate)
Red sand ‘road’ into Aspley Heath
Some of the 13 adventurer’s heading off to the woods….
Brown sand & Ironstone ‘Pavement’
‘Road’ cutting with exposures
John’s trowel with examples
Ironstone with fossilised wood.
Ironstone external mould of possible Pholadomya.
Danesborough iron age Hill Fort. Extensive remains of rampart and ditch defences. Wavendon Woods.
Beech and pine trees
St. Mary Magdalene, Little Brickhill Church. (John Wong)
Part of the Church wall. Ironstone+clay tiles+Totternhoe Stone. (John Wong)
Giant Ironstone blocks, 5 – 10 tons each for building work.
Waiting to be cut out.
Almost falling out of the hill side.
Ironstone 180my.
St. Michael & All Angels Church, Great Tew, Oxfordshire. Ironstone built, c1400 A.D.
Ammonites from the quarry.
Crystals of Gypsum from the clay.
Details of the Ammonites.
Ironstone pieces & Clay from the quarry.
Rhynchonellid Brachiopod found by John Wong
180my Ironstone Nautilus (11 kilos) with its smaller modern relation-Found by workmen in the Gt. Tew quarry.
Another view showing sutures.
Swallow Holes at Water End, Hertfordshire (an SSSI) – GA Field Trip July 2016 with Mike Howgate. (he with the stick…..)
Potterells Stream ‘overflow channel’……..
……………disappearing into the underlying chalk to eventually join the river Colne.
A ‘Swallow Hole’ of Mimmshall Brook near North Mimms, just one of several in the area. These drain underground and eventually join the River Lea.
Thank you Sue Jacobs for the info and photos and two more below…
Lowestoft Ness, the most Easterly point in Britain. The sea defence blocks include gneiss + larvikite from Norway.
Reigate Lower Greensand ‘Caves’ where the white sand was extracted for glass manufacture in 19th c. Man-made self supporting tunnels due to the unusual quartz grains locking together and being strong in compression. If you want to visit, see ‘Links’ for the website.
Other interesting geological bits below……………
Phenocrysts of Feldspar in Granite + two close-ups
Thank you to Julia & Doug Daniels for the photos of some of their minerals, below.
Small Smoky Quartz
Rulilated Quartz
Morion- type of smoky Quartz
Small Amethyst
Rose Crystals
Morion
Amethyst Geode
Beautiful Carved Quartz Rose
Chalcedony – type of QuartzMike Howgate’s well attended field trip to Stonesfield, Oxfordshire, 2015.
The way down! Into the abyss. A ‘slate’ mine shaft which the bravest descended.
Not a very inviting entrance at the bottom of the shaft. But fascinating.
The Boss was there!
Health and safety headwear
This is why the village is called ‘Stonesfield’
An exposure of the limestone.
‘Slate’ uses.
The ‘Slate’ mine owner also provided refreshments……
Followed by a visit to Churchill, Oxfordshire
The Stonesfield photos supplied by Mike Howgate and Richard Furminger.
Some heavily disguised members of the AGS on a Field Trip to Dunstable in November 2014. They were looking for the source of the River Ver and only John Wong knew where it was…..
Was this it?
Thank you Sue Jacobs for the information and photographs.
Janice Nicholson sent me the three photographs below –
An interesting (oolitic) limestone tracery window in a Church in Essex with Anglo Saxon connections. Janice wondered what Winston Churchill was doing up there on the wall?
A very weather worn carved head of King ?
A sandstone Victorian viaduct in Scotland.Seed Fern. Natural History Museum (behind glass).
From ‘Advanced Text-Book of Geology’ by David Page. 1876. W.Blackwood&Sons. Original price 9d.
2.5cm. Twinned Crystal of Fluorite. Hilton mine, Scordale, Cumbria.
A jumble of ‘Tuning Fork’ Graptolites. Didymograptus murchisoni. Ordovician. S.Wales.
Turtle Coprolites in Limonite. Oligocene 30-35my. Washington State, USA.
Calcified Promicroceras Ammonites. Black Ven Marl, Charmouth, Dorset. Lower Jurassic. Photographed with kind permission Mr.Paddy Howe of The Fossil Workshop, Lyme Regis.
Marble cladding of unknown origin.
Pictures by RF
Cavansite on Stilbite – Pune, India.
Amateur Geological Society-North London 