Sunday, September 13, 2009

Millstone Grit

click photo to enlarge
The Yorkshire Dales are known for their limestone scenery and drystone walls. Places such as Malham, Ingleton and Sedbergh are visited by tourists keen to see the upland farms, caves, potholes, wild landscape and small villages of this picturesque area. The district known as Craven, which includes the market town of Settle, is visited for similar reasons. However, in this location geological faulting has produced a land that departs, in some areas, from the stereotypical Dales landscape.

Here the various lines of the Craven Faults have produced places where the ubiquitous Carboniferous Limestone meets the Millstone Grit that dominates the nearby Forest of Bowland. At these boundaries the light coloured limestone gives way to areas where the rock is darker, less obviously stratified, has fewer outcrops, and produces less scree. Close inspection of Millstone Grit shows that, like limestone, it was laid down under the sea: the stone is flecked by water-smoothed pebbles of white quartz. In the Millstone Grit areas the fields are less well-drained, feature more rushes, and are more acidic: pine trees, silver birch, oak and rhododendrons will grow where woodland has been encouraged. However, the drystone walls that are characteristic of the limestone areas are also found on Millstone Grit, though here more of the building material was produced by small-scale quarrying rather than scree scavenging and field clearing.

Today's photograph shows Lambert Lane above Settle. This route connects an area of Millstone Grit with one of Carboniferous Limestone. In my shot the nearer walls are constructed of the darker stone, but the most distant ones are limestone. At points between both kinds of rock are found in the walls. I took this photograph for the complexity of the walls at this juncture - the lane, the curved sheep fold and the two walls in the foreground that serve to channel sheep to a tunnel under the lane into an adjoining field. All these walls were built as a result of the Enclosure Acts, and were probably erected in the nineteenth (or possibly eighteenth) century. I felt my image would benefit from a figure to give a visual focus and some scale, so I stayed behind whilst my wife strode on ahead, and I waited for my moment to press the shutter.

photograph & text (c) T. Boughen

Camera: Olympus E510
Mode: Aperture Priority
Focal Length: 90mm (180mm/35mm equiv.)
F No: f6.3
Shutter Speed: 1/160
ISO: 200
Exposure Compensation: 0 EV
Image Stabilisation: On