Wonders of the Peak

Buxton Museum & Art Gallery

Geology

Ilam Rock

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Ilam Rock © Andrew Dennes via Flickr (CC BY-NC-ND 2.0)

These delicate fingers of rock on opposite banks of the Dove are one of the scenic highlights of the dale. Amazingly, the 25m- high leaning finger of Ilam Rock has several rock climbing routes up its precipitous sides, while Pickering Tor has a gaping cave at its foot.

Both were left stranded as free-standing pillars of hard reef limestone when the softer rock was eaten away by the glacial meltwaters of the last Ice Age. Artist JMW Turner captured Ilam Rock in a popular painting, which undoubtedly contributed to our view of this as a sublime landscape and reinforced it as a place of interest to visiting tourists over the years.

The path now swings east opposite Hall Dale to pass the impressively-yawning water-worn cavities known as Dove Holes. Beyond here, the riverside path passes a number of weirs before running under the impressive vertical cliff of Raven’s Tor. A gentle meadowland path, rich in lime-loving flowers such as rockrose and thyme, now takes you into the hamlet of Milldale, which is reached by crossing the narrow Viator’s Bridge

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The Central Weir

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The head of water behind this big weir once provided the power for another mill just downstream. This thunderous cataract, at the confluence of two rivers, is a good place to think about the elemental forces which gave rise to this landscape.

The central weir © Simon Corble

It is hard to believe today but the River Goyt once took an entirely different course. Where we stand now would have been nothing but solid sandstone. The change came 2.5 million years ago when the Earth went through a series of Ice Ages. The planet’s temperature dropped and vast areas were covered in huge ice sheets.

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The rock face in the Torrs

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What a complete change of atmosphere down here at the bottom of the gorge! The noise of the town is completely drowned out by the cascades of water. The sound is echoed off these tall stone cliffs and massively impressive viaduct arches.

Sandstone cliff and viaduct © Simon Corble

Take a look at their stonework and then back at the rock face. Yes, it is indeed the same kind of rock, a tough sandstone. All of it was quarried right here. What would have been a much narrower gorge has been made wider from quarrying, leaving quite a smooth surface – now a proper challenge for local rock climbers.

One of this sandstone’s features is variability; some of it is coarse-grained, suitable for those massive blocks in the pillars, while elsewhere it is fine-grained and ‘flaggy’ – in other words it can be split into thin slices. Stone floors and even roofing slates for houses and mills could be made from this type.

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The Confluence with Black Brook

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Here is another major convergence of streams, adding yet more power to the River Dane as it carves its way down towards the Cheshire Plain. This is where Black Brook joins the river. Look in the water and we can see how Black Brook got its name.

If there has been a lot of rainfall, the water may look like strong tea, without milk. This dark brown colour comes from peat staining the water. Peat is found on the high moors where both the River Dane and Black Brook have their origins

Black Brook is fed on one side by water running down from the back of an escarpment called the Roaches.  Their name comes from the Norman French word ‘roches’, meaning simply ‘rocks’. There are some dramatic cliffs and spectacular wind-sculpted rock formations up there – well worth exploring another day.

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Lud’s Church exit

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Before we leave the magic of Lud’s Church completely behind, we ought to consider how such an extraordinary feature came to be. Of course, there is a folk tale involving the Devil making a giant gash in the earth with his finger nail.  More logically, can you find any signs of erosion, by water for instance?

This in no way looks like one of those small, water eroded cloughs. In fact, there is no sign at all that a stream has ever run in or out of here. For the record, Lud’s Church is around 17 metres deep and 100 metres long. The sides may be jagged, but they are straight drops of gritstone, draped with cushions of soft moss. There is not much of an eroded look about them.

Think back to the wider picture, though. The River Dane managed to find a passage through the hard gritstone wall of the Roaches somehow. There must have been a weakness. In fact the gritstone of this whole area is traversed by numerous ‘faults’ – cracks inside the rock. These run northwest to southeast, just as Lud’s Church does.

Where the bed of gritstone dips to the north, into what is known as the ‘Goyt Syncline’, a large mass of it simply cracked away. The rock slipped downhill a few metres, breaking along one of these fault lines. This sudden movement under the force of gravity opened up the chasm as we see it today.

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Castle Cliff Rocks

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Castle Cliff Rocks is in effect the last formation of the Roaches, though we are many metres below the heights of the escarpment. A brief clamber on a few of these boulders is fun and will help you appreciate why the Roaches is a mecca for rock climbers. Please do take care here, however, especially in wet or icy weather.

This type of rock doesn’t crumble easily and offers a firm grip. Officially known as Roaches Grit, it is very hard sandstone. It formed from coarse sand washed down into a huge river delta during the late Carboniferous period, some 320 million years ago. This rock is a subdivision of the famous Millstone Grit found widely across the Peak District.

The stack here has survived because this is a particularly hard section of rock. It has withstood the eroding efforts of rain, ice and wind much better than the less durable material which must have once surrounded it.

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