Old Harry Rocks in Dorset. Photograph: Adam Wearing/Getty Images/500px

Thanks to the Guardian for this long read on rocks and the people who dedicate their lives to studying them, and informing we lay people about them:

Rock of ages: how chalk made England

Swathes of England’s landscape were shaped by the immense block of chalk that has lain beneath it for 100 million years. For a long time, even geologists paid it little heed – but now its secrets and symbolism are being revealed

The Seven Sisters cliffs in East Sussex, England. Photograph: eye35.pix/Alamy

On the British Geological Survey’s map, chalk is represented by a swathe of pale, limey green that begins on the east coast of Yorkshire and curves in a sinuous green sweep down the east coast, breaking off where the Wash nibbles inland. In the south, the chalk centres on Salisbury Plain, radiating out in four great ridges: heading west, the Dorset Downs; heading east, the North Downs, the South Downs and the Chilterns.

Stand on Oxford Street in the middle of the West End of London and beneath you, beneath the concrete and the London clay and the sands and gravels, is an immense block of white chalk lying there in the darkness like some vast subterranean iceberg, in places 200 metres thick. The Chalk Escarpment, as this block is known, is the single largest geological feature in Britain. Where I grew up, in a suburb of Croydon at the edge of south London, this chalk rises up from underneath the clays and gravels to form the ridge of hills called the North Downs. These add drama to quiet streets of bungalows and interwar semis: every so often a gap between the houses shows land falling away, sky opening up, the towers and lights of the city visible far in the distance.

The British Geological Survey (BGS) was established (as the Ordnance Geological Survey) in 1835. The world’s first national geological survey, its original remit was to survey the country and produce a series of geological maps. Today, the BGS, which still produces the “official” map of the UK’s geology, is best described as a quasi-governmental organisation split between research, commercial projects and “public good”. Quite a lot of its work is now done outside Britain: at the time of writing, projects include studies of groundwater in the Philippines and volcanic activity in the Afar region of Ethiopia.

One week in early October, four members of the BGS set up camp in a self-catering cottage near the town of Tring in the Chiltern Hills, about halfway between London and Oxford. They were on a training exercise as part of a project to produce a new geological map of the chalk of southern England. On the day I arrived, the wooden table in the main room was covered with maps, books, a half-drunk bottle of red wine and a packet of chocolate digestives. Field leader Andrew Farrant, tall and thin, with steel-rimmed glasses, was drinking a cup of tea. He had a sort of leather holster attached to his trousers, from which swung a geological hammer with a surprisingly wicked-looking long, pointed end.

Farrant has been working on the chalk-mapping project on and off since 1996. “I would say that not enough attention is paid by the academic research community to understanding the geology of the UK,” he said. “If I was doing this [mapping project] in east Greenland, then I’d probably get funding for it – east Greenland is sexy. And people tend to think that because we have a geological map of the UK, it’s all been done, but actually you can still improve it.”…

Read the whole article here.