River Holford
Encyclopedia
The River Holford is located in the east Quantock Hills
Quantock Hills
The Quantock Hills is a range of hills west of Bridgwater in Somerset, England. The Quantock Hills were England’s first Area of Outstanding Natural Beauty being designated in 1956 and consists of large amounts of heathland, oak woodlands, ancient parklands and agricultural land.The hills run from...

 Area of Outstanding Natural Beauty
Area of Outstanding Natural Beauty
An Area of Outstanding Natural Beauty is an area of countryside considered to have significant landscape value in England, Wales or Northern Ireland, that has been specially designated by the Countryside Agency on behalf of the United Kingdom government; the Countryside Council for Wales on...

 in Somerset
Somerset
The ceremonial and non-metropolitan county of Somerset in South West England borders Bristol and Gloucestershire to the north, Wiltshire to the east, Dorset to the south-east, and Devon to the south-west. It is partly bounded to the north and west by the Bristol Channel and the estuary of the...

 England.

It is approximately 4.5 miles (7 km) long. Its source is at Lady's Fountain Spring, Frog Combe which is near Halsway and 250 m above sea level before flowing past Holford
Holford
Holford is a village and civil parish in West Somerset within the Quantock Hills Area of Outstanding Natural Beauty, and about west of Bridgwater and east of Williton. The village has a population of about 200. The village is on the Quantock Greenway and Coleridge Way footpaths...

 towards its mouth at Kilve
Kilve
Kilve is a village in West Somerset, England, within the Quantock Hills Area of Outstanding Natural Beauty, the first AONB to be established, in 1957....

.

The river is used as an outdoor classroom for students of Fluvial Geomorphology.

The geology of the river consists of three different rock types at the top of the river there is the Devonian Quartzite
Quartzite
Quartzite is a hard metamorphic rock which was originally sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to gray, though quartzites often occur in various shades of pink...

(Metamorphic
Metamorphic rock
Metamorphic rock is the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure causing profound physical and/or chemical change...

), in the middle of the river there is the Permo-Triassic Marl
Marl
Marl or marlstone is a calcium carbonate or lime-rich mud or mudstone which contains variable amounts of clays and aragonite. Marl was originally an old term loosely applied to a variety of materials, most of which occur as loose, earthy deposits consisting chiefly of an intimate mixture of clay...

(Sedimentary) and the lower part of the river consists of Jurassic Limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

(Sedimentary). The first two rock types are impermeable meaning there is little drainage for the river but the river depth becomes smaller as the water flows over the permeable limstone which will allow water to pass through. Quartzite is also very resistant to chemical weathering and can form ridges.

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