On the manufacture of gun-flints, Memoir of the Geological Survey 1879.

Title page of: Memoir Geological Survey. England and Wales. On the manufacture of gun-flints, the method of excavating for flint, the age of Palaeolithic Man and the connexion between Neolithic art and the gun-flint trade by Sydney B.J. Skertchly. London : HMSO, 1879. The memoir is an exhaustive account of the making of gun-flints at Brandon in Sussex.

The memoir is a regarded as a classic by modern day flint knappers.

Sample page showing descriptions of the thirty-three gun-flints that were available at the time. The gun-flints had interesting names such as Mixed Grey or Spotted Horse Pistol, Chalk-heeled Horse Pistol, Best Carbine, Solid Grey Musket etc. They were all made by eye, no measurements were involved.

Illustration showing knappers at work. Flint was mined from chalk pits, each pit lasting from six to nine months. The miners sold the flints to the flint knappers by the 'jag' which is one cart-load about equal to a ton. 

To manufacture the gun-flints there were four processes:

Drying - flint would be dried outside in the summer but in the winter it was dryed around the fire indoors.

Quartering - a block of stone is taken and quartered - they may weigh a quarter of a hundredweight to two hundredweights.

Flaking - The most difficult process and requires great skill and 'nicety of judgement'.

Knapping - The final process of forming the flakes into gun-flints. A good flake will make four, and a very good one five flints. An average workman will knap 3,000 flints in a day of 12 hours. One man working from 4 a.m. until 11 p.m. made 24,000 in a week!

Illustration showing how a flint fractures to provide a series of flakes. Just one stage in the process of making gun-flints.

Watch a video on flint mining and knapping at Brandon in the 1930s and 1940s here  and here. Definitely worth watching!

Posted by Bob McIntosh

Flints from Piltdown, Sussex

These flints were found in a gravel pit at Piltdown in Sussex by Charles Dawson (1864-1916), a local solicitor and amateur archaeologist. The gravel pit was the same one in which the now infamous Piltdown Man was discovered. It is widely believed that Dawson was responsible for this audacious fraud.


BGS image ID: P903735

BGS image ID: P903736

BGS Image ID: P903738

BGS has a Piltdown Forgery webpage and timeline which can be accessed here

Andrew L Morrison

Penmaenmawr Mountain Top Quarry

BGS Image ID: P539567

Penmaenmawr Mountain Top Quarry. Conveyors down to loading pier.

BGS Image ID: P539617

Ship loading jetty - some of output went by boat to London.

BGS Image ID: P539574

Drilling shot holes.

Images from the Hugh O'Neill collection. Photographs taken c 1960-61.

Posted by: Bob McIntosh

English churches - building stones

BGS Image ID: P209976

Drewsteignton village square, Devon. Looking east. Drewsteignton village is sited high on the northern edge of Dartmoor. Holy Trinity Church and Church House with its large chimney stack are both built of Dartmoor granite blocks. Drewsteignton village is typical of many on the the northern fringe of Dartmoor. The church tower is built of Dartmoor granite (imported to the district). The house to the right of the lych gate is built largely of rough hewn granite blocks. The wall to the left of the lych gate is built of blocks of impure limestone and hornfelsed mudstone from the local quarries (now disused). The granites of Devon and Cornwall and their associated intrusive and metamorphic rocks have commonly been worked in the past for building stone, both for local housing and for major building projects elswhere in the United Kingdom such as the many 19th century dock construction schemes in London.

BGS Image ID: P210728

Snettisham Church, Norfolk. Looking east. This large, late medieval church at Snettisham is typical of many in this area where a mixture of local building stones are used for the main walling material, chalk, flints and ferruginous carstone, with better quality oolitic freestones of the Lincolnshire Limestone Formation imported for more ornate mouldings and carved stonework. Built in the 14th century decorated style, Snettisham Church has its nave and tower constructed of partially dressed blocks of chalk and flint. The spire, pinnacles, copings, buttresses and window tracery are made of oolitic limestone, one of the Middle Jurassic freestones. The wall in the foreground is made of dressed Carstone blocks which have suffered some frost damage. While this area of Norfolk produced a wide variety of local building materials, including sandstones, limestones and flints, none were good enough to qualify as freestones. Consequently from medieval times onwards the oolitic limestones of Lincolnshire were commonly imported for the stonework in all the more prestigious buildings.

BGS Image ID: P210855

St Mary's Church, Purton, Wiltshire. Looking north-west. This Norman / Medieval church with its spire and crossing tower is constructed of Jurassic Coral Rag limestones. The term Rag refers to the coarse grained shelly (or ragged nature) of the limestone when fractured. The ragstone beds are generally very hard and durable stones but are consequently, therefore, very difficult to work, commonly they are used as undressed rubblestone blocks. This church at Purton is largely built of local 'Coral Rag' Limestone from the local Osmington Oolite Formation.The roof of the church is covered with stone slates which in this area are likely to be from the Forest Marble Formation, although some use of local Purbeck limestones is also known. The hard, pale grey, coarsely oolitic and shelly limestones of the Corallian Group were widely used in buildings along their outcrops in Dorset, Wiltshire and Oxfordshire.

Posted by Bob McIntosh

BGS maps portal — maps and sections 1832 to 2014

Sheet 10 [Isle of Wight, Lyrnington, part of Portsmouth Harbour.] Geological Survey of England and Wales Old Series. 1:63,360. 1856.

Two sheets separated by 157 years. Both available as high resolution scans on the new BGS Maps Portal  

Isle of Wight special sheet. Geological Survey of England and Wales 1:50,000 map. 2013

The British Geological Survey (BGS) has  released high resolution scans of over 6000 geological maps which were previously published on paper. The “BGS Maps Portal” provides free to view small and medium scale maps produced by the BGS since geological mapping began in 1832. The Maps Portal includes the recent 1:50,000 mapping of England, Wales and Scotland, geochemical and geophysical maps and also the historical maps that were in the former BGS historical maps website. 

Posted by Bob McIntosh

Franklin's Ships: Records from HMS Erebus and HMS Terror

‘Term day books’ from HMS Erebus and HMS Terror, 1840-1842, containing both magnetic and meteorological observations.

Sir John Franklin’s fabled lost expedition, back in the news last week after one of the ships was found by Canadian search vessels, was not the first time that the two ships HMS Erebus and HMS Terror set sail together on a voyage of exploration. Six years before Erebus and Terror departed England for the Arctic, they were beginning a four year expedition that would take them southwards to the Antarctic. On that journey they were led by Captain James Clark Ross, an experienced polar explorer, with the second in command (and commander of HMS Terror) being Francis Crozier. Crozier was captain of the same ship on Franklin’s expedition, and is reported to have taken charge after Franklin’s death, with some suggestions that he survived for several years afterwards. 

One of the aims of both Ross’s Antarctic expedition and Franklin’s Arctic one was to collect magnetic data, and the data relating to the Antarctic can still be found in BGS’s collections today. Both HMS Erebus and HMS Terror recorded information relating to the earth’s magnetic field, as well as making meteorological observations such as details of aurora sightings. BGS holds similar records of many other Royal Navy ships, with data collected around the world throughout the nineteenth and early twentieth centuries. A list of Royal Navy ships’ geomagnetic log books held by BGS can be found here. Records of Ross’s expedition also live on in the names of many Antarctic landmarks – for example the Ross Ice Shelf, Ross Sea, and Ross Island with its two volcanoes Mount Erebus and Mount Terror.

See below for more images of records from HMS Erebus and HMS Terror.

Term day book and other papers containing magnetic and meteorological observations from HMS Erebus, 1840-1843. James Ross’s signature can be seen in the centre.

Magnetic observations taken at Auckland Island (to the south of New Zealand), 5^th December 1840, and Van Diemen’s Land (now Tasmania), May 1841, from HMS Erebus.

Papers from HMS Terror, 1841-1842. The document on the right compares magnetic observations from HMS Terror with those made at Ross Bank, Tasmania. 

Francis Crozier’s signature on a document recording auroras seen from HMS Terror in March 1842.

Forth Road Bridge construction. 50th Anniversary

BGS image ID: P537923

A main lift. Images from the Hugh O'Neill collection of the construction of the Forth Road Bridge.

BGS image ID: P537924

South pier.

BGS image ID:  P537894

Tensioning cables.

BGS image ID: P537898

Institute of Quarrying visit

BGS image ID: P537895

Tension cables.


Posted by Bob McIntosh

Haematite vein from Eas an Fholaich, near Loch Eilt, west of Fort William

BGS Imager ID: P527666

Part of a haematite vein from Eas an Fholaich, near Loch Eilt, west of Fort William, Invernessshire. British Geological Survey Petrology Collection sample number MC 7446. 

Haematite is an iron ore mineral composed of iron oxide. It belongs to the hexagonal crystal system and can occur as stubby black rhombohedral crystals or more commonly massive, granular masses, compact, or soft and earthy. It has a dark cherry streak. There is evidence that haematite in veins has been known in Scotland from a very early date. In the middle of the 18th century haematite was mined at Tomintoul, Pennel Burn in Ayrshire and at Garleton in East Lothian. Iron ores come in many forms from bog iron ores, sedimentary bedded ores, to ore deposits injected as metalliferous intrusions. Haematite is often in the latter category.

Posted by Bob McIntosh

Mining subsidence in Ferniehill, Edinburgh, 2000

BGS Image ID: P100363

Ferniehill, Gilmerton, Edinburgh. Limestone mine subsidence event, November 9th 2000 to March 2001; 'Tumbledown Terrace'. The subsidence has caused damage to buildings, roads etc. The Carboniferous Gilmerton Limestone was quarried and mined at Ferniehill from time immemorial until about 1829. Collapsing old limestone mineworkings were responsible for what became catastrophic damage to many properties.

Download a leaflet explaining the subsidence, by Mike Bowne

BGS image ID:  P100365

BGS image ID: P100398

Posted by Bob McIntosh

William Smith, Geological section from London to Snowdon, 1819

William Smith: Geological section from London to Snowdon showing the varieties of the strata and the correct altitudes of the hills. Published: London : J. Carey, 1819.

Extract from William Smith's Geological section from London to Snowdon showing the Stonebrash Hills, the Chalk Hills and the intervening Vale of Isis and Vale of Aylesbury.

Extract from William Smith's Geological section from London to Snowdon showing the mountains of North Wales.

The section came with an accompanying 'Legend'.

Posted by Bob McIntosh