Why does the mystical Glastonbury Tor rise up out of the surrounding lowlands?

First of all look straight ahead and in the middle distance you’ll see three hills which punctuate the flat landscape. From left to right they are Hay Hill, Ben Knowle Hill and Yarley Hill, part of a low ridge just south of the River Axe.

 Surrounding these hills the Somerset Levels are an area of low-lying farmland. The lowest point is just 0.2 metres above sea level.  Six thousand years ago the levels were not land at all but a shallow lake dotted with higher islands. Glastonbury Tor at over 500 feet is one of these. Its Celtic name was Ynys Wydryn, meaning ‘Isle of Glass’.

In the nineteenth century this boggy area of freshwater fens and salt marshes was artificially drained and the land reclaimed for pasture. Today the low-lying levels make the perfectly conical Glastonbury Tor and the other hills stand out in sharp relief. 

The tor itself is formed of rocks that date back to the early Jurassic Period between 200 and 175 million years ago and was once part of a bigger ridge of rock that crossed the levels. Over time the softer rocks around it have been worn away by weathering (wind, rain, snow and ice) scouring some parts away and leaving other parts standing. Glastonbury Tor has withstood these processes thanks to a tough rock called sandstone.

One of the top layers of rock that make up the tor is sandstone which has acted as a caprock sealing and protecting the lower rocks from erosion. At the bottom of the tor an iron-rich spring infuses the sandstone with iron oxides which in turn make it even more resistant. 

Mist and myth

The low-lying damp ground at the foot of the tor can produce a visual effect known as a Fata Morgana when the tor appears to rise out of the mist.

This optical phenomenon occurs because rays of light bend when they pass through air layers of different temperatures. The Italian term Fata Morgana comes from the name of Morgan le Fay, the sorceress and half-sister to King Arthur. 

Mystic mountain

View from Deer Leap towards Glastonbury Tor © Mendip Hills AONB

Deer Leap viewpoint

From this stunning vantage point we have sweeping views south across the flat land of the Somerset Levels. On a clear day, looking east you can see the dark line of hills marking out Exmoor National Park and if you look in a west south-west direction you can even spot the Bristol Channel glistening in the distance.

As our eyes pan across the view they rest on a perfectly rounded knoll with a short tower on top. This is Glastonbury Tor. Claimed as the site of the legendary Vale of Avalon and the final resting place of King Arthur, the tor rises up above the flat land surrounding it and is visible for miles around.

Why does the mystical Glastonbury Tor rise up out of the surrounding lowlands? Click to reveal the answer

Location: Ebbor Gorge, Somerset, BA5 3BA
Grid reference: ST 52649 48742
How to get there: Park at Deer Leap car park and picnic area (on the road between Wookey Hole and Priddy)
Keep an eye out for: Buzzards and other birds of prey soaring on the thermals below

Deer Leap viewpoint credits

Thanks to:

Andy Mallender and Mendip Hills AONB for suggesting the view and advice on the text

'Tor' may originate from a Cornish word for 'belly' which explains its gently rounded shape!