Chilterns Chalk

A virtuous circle: life became rock that supported our lives, literally, and has once again become abundant life.

A Chilterns story that is a mere 90 millions years in the making.

Ninety million years ago, a great ooze was accumulating at the bottom of a sea. Microscopic creatures, coccoliths, their shells made of calcite extracted from the rich seawater were contributing to the ooze.  As they died, and their minute shells and skeletons settled onto the seabed of a tropical sea, a substantial layer gradually built up over millions of years until it all eventually consolidated into rock. Chalk. This geological layer can be followed right across Western Europe where evidence of mining and quarrying both above and beneath the ground can be found.

Chalk is a soft, white, porous, sedimentary carbonate rock, a form of limestone composed of the mineral calcite

Not only is chalk a part of our national conscious, the dramatic and iconic white cliffs of Dover shown in times of national crisis, it also acts as a natural reservoir, releasing water slowly into another feature of the Chilterns – the chalk streams. Givers of life. 

A Chilterns story that is a mere 90 millions years in the making.
The seam of chalk emerges to the south east, along the English Channel

From hard industry to site of special scientific interest

The Chilterns and our story, are in fact all about chalk; it is the geological formation that defines our landscape, industry, people, wildlife and wildflowers. But it’s not all a chocolate box image; quarrying for cement saw numerous sites across the region busy with extraction during the last century. Some still remain, others are filled with waste water and submerged cables, making them an ideal haven for birdlife and illegal parties! One successful transformation from working quarry to wildlife sanctuary that you can visit, is College Lake near Tring, home to migratory birds and bird enthusiasts.

These microscopic bits of shells and dissolved skeletons, layer into white cliffs and layers of London…and in the space that is left behind, layers of abundance across the year.

A Chilterns story that is a mere 90 millions years in the making.
Late summer blooms

To wander around my local quarry, you’d be forgiven for thinking it had always contained wildflowers, badgers, butterflies and skylarks, yet this former cement quarry has been transformed into a designated Site of Special Scientific Interest. It was once part of much larger cement works ‘Castle Cement’, with large silo’s and 350ft chimney’s that became a local landmark. The quarry operated from 1937 until closure in 1991 and the chimney’s demolished in 1998, before a large housing development took shape on part of this brownfield site. The remainder has been left to nature.

An image of the former excavations at Castle Cement
The excavation of a tropical seabed

All around are scattered industrial archeology: rail tracks, cables, coils, metalwork embedded in the chalk, rubble, rotten sleepers, fence posts, bleached signs, signposts, mysterious shafts, ruts and excavations.

I am reminded every day of the special qualities that bring such an abundance of life to what should be sterile space. Most noticeable being the countless butterflies that rise up and dance around my legs as I walk along the narrow chalk pathway in the summer; chalk hill blues, an adonis blue, small skippers, small coppers and more marble whites than I have ever seen. These are adapted to the chalk grassland and the myriad of wildflowers that keep them in nectar throughout the summer. 

A Chilterns story that is a mere 90 millions years in the making.
Butterflies on the wild marjoram

And of course there are the fabulous orchids; the common spotted-orchid, common fragrant-orchid, incredible bee orchid, lady orchid, pyramidal and military orchids. At their best in early June, competing with the carpets of oxeye daisies to be star of the wildflower show.

Common spotted orchids
Common spotted orchids

If you want to see the Chilterns, ask a dog walker

Throughout the seasons, there is activity here. Heavy snowfall brings the children out to sledge down the steep slopes, their shrieking voices carrying across the quarry. When the winter and early spring have been very wet, the water table, not far beneath the surface, rises and floods any depressions and gulley’s, gravity ensures the overflow finds its way to the lower lying ground, flooding badger sets and rabbit warrens. The wind is cold, the chalk slippery underfoot. The skylarks arrive in late winter, announcing the start of the breeding season with their distinctive overhead song.

The soft mists of spring can be eerie, but they are another sign of the advancing seasons. After years of dog walking, I now know what signs to expect as the quarry slowly emerges after winter. March can seem an impatient month before the trees and shrubs get going in waves of vivid green, pale yellow and white blossom. Wildflowers across the quarry floor, bloom in waves of yellow, white, purple, sprays of white and more yellow, before everything at ground level is claimed by the wild grasses. Now grown tall in the late summer, each scratchy in shades of khaki, before the farmer comes in to mow in late autumn. Sweet-tasting summer goodness for his cattle long into the depths of winter. 

A Chilterns story that is a mere 90 millions years in the making.
The quarry cliff-edge too step to hold the snowfall

A virtuous circle

That something so ancient, and yet so simple, could have so many uses across the ages is humbling. What comes from an ancient tropical seabed has a place in our national psyche, as well as a place in the story of the Chilterns. And now, as we seek an escape from our busy lives, these transformed spaces take us back to nature. Back to our own story. A virtuous circle: life became rock that supported our lives, literally, and has once again become abundant life. 

A Chilterns story that is a mere 90 millions years in the making.
Common century, or bloodwort

Further Information

Enjoy Tring reservoirs, College Lake and Grand Union Canal on this 13km circular walk.

Forget M&S orchids, manicured to within an inch of their pampered lives and head instead to the nearest Chilterns summer meadow to indulge yourself with our own exotic orchids.

Here are more ideas and places to enjoy the Chilterns in the Summer.

A Chilterns story that is a mere 90 millions years in the making.
Mists of white

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