Malham Cove and Malham Tarn

Malham Cove

Malham Cove is a curved crag of carboniferous limestone formed after the last ice age.  Meltwaters, particularly from Malham Tarn, cut back the cove as they fell over the edge as a waterfall. This erosion took place more actively at the centre of the lip of the fall rather than at the sides, hence the curved shape.  The cliff is approx 250 feet high and 1500 feet wide. Water easily finds it way down through the many joints and fissures in the limestone and therefore the water table never rises high enough to make Malham Cove the waterfall that it once was. Although it has been reported that water flowed over the cove after heavy rainfalls in the early 19th century.

The stream that emerges from under the cliff of Malham Cove comes from the Smelt Mill Sinks, three-quarters of a mile north west of the Cove on the moor. It is mistakenly thought of as the source of the River Aire. However water from the tarn disappears at Water Sinks and flows at a deeper level until it rises south of Malham village as the Airehead Springs - the true source of the River Aire.

Variations in the hardness of the limestone layers cause the very noticeable horizontal ledges in the cove face.  The dark vertical stripes are formed by the lichens and mosses that grow in the water that seeps down the face of the rock.  Soot and dirt in the air gets caught on the growth and this also changes the colour of the rock.

Malham Cove The emergent stream Climber on Malham Cove Hart's Tongue Fern

The magnificent limestone pavement on the surface of the Cove is deeply fissured into a pattern of channels. Chemical weathering, due to the slightly acidic rain, dissolves and widens the many joints of the limestone carving the patterns that can be seen today. The resulting limestone pavement is made up of 'clints' or 'grikes', where the naked limestone lumps are the clints and the fissures in between are the grikes. The grikes are home to many rare (shade-loving) plants - harts-tongue fern, wood-sorrel, wood-garlic, geranium, anemone, rue, and enchanter's nightshade.
 

Malham Tarn

Malham Tarn lies on a floor of impervious slate covered with thick glacial drift and marl deposits. It is a natural upland lake that sits on a bed of slate that was brought to the surface by the North Craven fault.  It has a surface area of around 150 acres, its average depth is approximately 2.4 metres and the maximum depth is around 4.4 metres.

The tarn was dammed by a moraine when the glacial ice-sheet retreated at the end of the last ice age.  The tarn was originally twice its present size, however silting has reduced its size.  In 1791 the level of the tarn was raised by approximately four feet (1.2m) when a dam and weir were constructed the at Tarn Foot by Lord Ribblesdale. The previous shore-line and beach is now a drowned landscape.  Tarn Moss is a raised bog to the west of the tarn which has developed at the mouth of the tributary streams coming off Fountains Fell.

The one outflow stream only flows for a short distance before sinking into the carboniferous limestone when it reaches the line of the north craven fault at Water sinks.  It then re-emerges further down the valley at Airehead Springs.

Looking across Malham Tarn Malham Tarn

 
Recommended Walk
Penyghent from Horton in Ribblesdale

Gordale Scar and Janet's Foss

Gordale Scar

To the north of the Mid Craven Fault at the Malham is Gordale Scar, which was carved as a meltwater channel beneath the glacial ice-sheet. The sides of this gorge overhang to a considerable extent, suggesting that there was once a great cavern, the roof of which has subsequently collapsed. Remnants of this roof can been found on the right above the first waterfall. The left side of the cavern has vertical joints that divide the limestone into thin plates sometimes less than an inch in thickness.

Entrance to Gordale Waterfalls at Gordale Scar Gordale Scar

The waterfalls flow over large masses of tufa, more of which can be found further downstream at Janet’s Foss a short distance south of the scar.  Above the waterfalls the valley stretches for a mile as a deep trench in the limestone plateau, much of which 100 to 150 feet deep, walled by almost vertical limestone cliff. Gordale Beck winds down the many interlocking spurs of the vertically jointed and horizontally ledged rock on its way to Gordale Scar.
 

Janet's Foss

Foss is the old norse word for a waterfall or force and Janet (or Jennet) was believed to be the queen of the local fairies who lives behind the fall in a cave.  Janet’s Foss falls over a moss-covered tufa screen.  The tufa extends from the lip of the fall down to the level of the pool. The calcium rich Gordale Beck, causes some of the calcite to be deposited over the moss and forms tufa.

There is a cave behind the waterfall Janet's Foss Woods at Janet's Foss

Slowly over the years the deposited tufa has grown forward to form the apron which we now see today. Under the waterfall there is a curved fold in the limestone under and a cave, known as Janet's cave. According to legend, this is where Janet lived.  However according to the records, this was once inhabited by smelters working the copper mines at Pikedaw to the west.  There are also records that state that the pool beneath Janet's Foss was once used by shepherds for washing and cleaning their sheep before taking them to the markets.
 

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