Seeking the Teesdale Assemblage, County Durham, England

The Durham Dales often take one a tiny step beyond the magic. While their more illustrious southern neighbours, the Yorkshire Dales have their own unarguable beauties, I always feel that Weardale and Teesdale offer just that little bit extra. And they have an uncanny habit of tossing the odd free gift into the mixture when you are least expecting it.

I met with five friends at around 9.30 am in the car park of the Bowlees Visitor Centre in Upper Teesdale. At an unhurried pace, we crossed a field to the pretty cataract of Low Force and continued over Wynch Bridge to the southern bank of the river. The present structure, dating from 1830, is a replacement of the original, which was built in 1741, and is said to have been England’s first suspension bridge.

In Your Bucket Because…

  • Upper Teesdale is one of the most wildly beautiful places in England.
  • The short walks take you to two of the most spectacular waterfalls in the country.
  • The collection of rare wild flowers found here can be seen nowhere else.
  • The geology, both here and in the wider North Pennines is amazing.

High Force

We followed the bank upstream, past clumps of globeflower, water avens and the occasional orchid, while the damp fields to the south were a golden glow of marsh marigolds. Lapwings, curlews and oystercatchers flew over the fields. The dippers that are usually seen along this stretch of the Tees seemed to have abandoned the river to the Armada of canoes and kayaks that negotiated the rapids. Passing one of the largest juniper forests in the country, we heard the first sounds of crashing water, and a short detour brought us to a belvedere overlooking the magnificent High Force.

High Force

High Force

This is not, by a long way, as is sometimes claimed, the biggest waterfall in England, but it is certainly one of the most impressive. The dominant rock type in Upper Teesdale is the dolerite of the Great Whin Sill, a volcanic intrusion that forced its way through the more ancient limestone some 295 million years ago, and is exposed at various places throughout north-east England, most notably on the Farne Islands and along Hadrian’s Wall. At High Force, the vertical columns of the Whin Sill rest above the horizontal beds of limestone. Through the millennia, the softer limestone has crumbled under the hammering of the water, so that, without support, the upper rocks have collapsed from time to time. The result is that High Force has cut its own gorge up the valley, into which it has retreated 700 metres.

Having gazed our fill at the spectacle, we returned to the recently refurbished Bowlees for a leisurely lunch, then headed farther up the valley to the reservoir at Cow Green.

Cow Green Reservoir

Cow Green Reservoir

Cow Green and the Teesdale Assemblage

This is a wild place, bleak, treeless and a complete contrast to the wooded slopes lower down. During the 1960s, construction of the dam caused controversy, as its waters inundated 312 hectares of scientifically important habitat, containing rare plants found almost nowhere else in the British Isles. The unique collection of flowers, known as the Teesdale assemblage, consists of Alpine and Arctic plants that have survived here since the last Ice Age. They include mountain pansies, violets, spring sandwort, rockrose and the insectivorous butterwort and sundew.

Spring Gentian

Spring Gentian

Rarest of all is the vivid blue spring gentian, which grows only in this tiny area and in the rocky Burren of the West of Ireland. Normally, the gentians are hard to find, but today we were lucky. We found a dozen nestling in a hollow at the edge of a limestone pavement near the car park. And as we continued along the road toward the dam, we spotted more, even outnumbering the usually more plentiful mountain pansies. In a small depression grew a cluster of another scarce flower, the birds-eye primrose, also found only here, and which has been adopted as the emblem of County Durham.

Cauldron Snout

Not to be outdone by its botanical surroundings, the geology showed us one of its rarities in an almost quarry-like patch of sugar limestone. Despite its name, this is, in fact, a metamorphic rock, a crumbly form of marble, which was formed when the heat and pressure of the Whin Sill magma cooked the surrounding limestone during the estimated fifty years it took to cool to solidity.

Cauldron Snout

Cauldron Snout

We passed the dam and descended the rough track to the top of Cauldron Snout. In some ways, this is even more impressive than High Force. With a height of 60 metres, it is the ninth highest waterfall in England, though its 180-metre cascade down the dolerite steps, makes it the longest in the country.

But what about those free gifts I mentioned? Well we found one, though we might just as easily have missed it. On the grass verge by the roadside, as we approached the edge of the dam, almost unnoticeable but just waiting to be seen if we happened to glance in the right direction, lay an exquisite Emperor moth, basking in the sun but keeping a low profile against the gusting wind.

 

Practicalities

  • Both of the walks described are approximately three miles return and follow easy hill tracks with little gradients. Much of the walk between Cow Green car park and the dam is on a surfaced road.
  • There is a shorter walk to High Force from the eponymous hotel above the waterfall, but a fee is charged for this.
  • A regular bus service runs through Teesdale from Barnard Castle, stopping at Bowlees Visitor Centre and Langdon Beck. The latter is a three-mile walk or drive from Cow Green.

 

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