The River Twiss is a river in the county of

Yorkshire Yorkshire ( ) is an area of Northern England which was History of Yorkshire, historically a county. Despite no longer being used for administration, Yorkshire retains a strong regional identity. The county was named after its county town, the ...

, England. The source of the river is Kingsdale Beck, which rises at Kingsdale Head at the confluence of Back Gill and Long Gill in the

Yorkshire Dales The Yorkshire Dales are a series of valleys, or Dale (landform), dales, in the Pennines, an Highland, upland range in England. They are mostly located in the Ceremonial counties of England, ceremonial county of North Yorkshire, but extend into C ...

. Beneath Keld Head, the river changes its name to the River Twiss. It has two notable waterfalls, Thornton Force and Pecca Falls, and its course follows part of the Ingleton Waterfalls Walk, then through Swilla Glen to Thornton in Lonsdale and down to Ingleton, where it meets the River Doe to form the River Greta. The English landscape artist

J. M. W. Turner Joseph Mallord William Turner (23 April 177519 December 1851), known in his time as William Turner, was an English Romantic painter, printmaker and watercolourist. He is known for his expressive colouring, imaginative landscapes and turbu ...

was a frequent visitor to the area, and his sketch of Thornton Force in 1816 is currently part of the Tate collection.

Course

From the caves below Keld Head, water flows and combines with Kingsdale Beck to form the River Twiss. It flows south over Thornton Force and Pecca Falls and through woodland to join the River Doe at Ingleton.

Waterfalls

The drop of Thornton Force is about . Pecca Falls has three drops totalling that fall into their own deep pools.

Geology

In its upper part, the river flows through a valley carved into horizontal beds of Carboniferous Great Scar limestone. At Thornton Force, it crosses a notable

unconformity An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval ...

into the underlying, steeply inclined

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...

greywacke Greywacke or graywacke ( ) is a variety of sandstone generally characterized by its hardness (6–7 on Mohs scale), dark color, and Sorting (sediment), poorly sorted angular grains of quartz, feldspar, and small rock fragments or sand-size Lith ...

s. The unconformity is clearly visible in the face of the waterfall. The Ordovician strata influence the character of the steep and narrow Swilla Glen and its waterfalls until, just north of Ingleton, the river crosses the

Craven Fault The Craven Fault System is the name applied by geologists to the group of crustal faults in the Pennines that form the southern edge of the Askrigg Block and which partly bounds the Craven Basin. Sections of the system's component faults whi ...

and onto Carboniferous Limestone once again.

Crossings

* Ravenray Bridge (foot) * Pecca Bridge (foot) * Manor Bridge (foot) * Unnamed Road, Ingleton

Gallery

Sources

Ordnance Survey Open Data https://www.ordnancesurvey.co.uk/business-government/tools-support/open-data-support

References

{{DEFAULTSORT:Twiss Rivers of North Yorkshire 2Twiss Ingleton, North Yorkshire