Tag: Coxley Quarry

Sketching Smeaton

SmeatonSmeatonWriting my nature diary for the January edition of the Dalesman magazine, I got sidetracked by the story of John Smeaton (1724-1792), ‘the father of civil engineering’. He only has a walk-on part in my article, where he described the rock in Coxley Quarry as ‘the best Blue Stone’ he had ever seen (I’ve come up with a theory of why he described the buff sandstone in the quarry as ‘Blue Stone’).

He visited the quarry in 1760 when he was acting as superintendent engineer on what would become the Calder and Hebble Navigation. The year before he had completed the construction of the Eddystone Lighthouse, which he designed to have the proportions of the trunk of an oak tree.

SmeatonHe’d also recently been awarded a medal by the Royal Society for his work on the mechanics of waterwheels and windmills. His enquiries into the relationship between pressure and velocity for objects moving in air led to a formula for calculating lift that the Wright brothers used in designing their aircraft.

Coxley QuarryI wanted to draw Smeaton looking suitably dynamic for my article but for the main illustration we’re going for an acrylic on board painting that I made on location twenty years ago in 1996.

Ironstone Concretion

Lens of white sandstone in Coxley Quarryironstone noduleLike a ripple on a pond or a blot on a page ironstone concretions spread out across the layers of sandstone in Coxley Quarry so I guess that they must have formed after the sandbanks were laid down, perhaps during the process of solidification.

There’s a sausage-shaped patch of pure white sand a couple of feet across which is encased in a rusty crust. It looks as if the iron has been leached out by a mineral-rich solution and I guess that this then bubbled upwards through the sand because above the lens of white there’s a knobbly network of weathered-out rusty chambers.

rolled ironstone noduleThere are also rolled pebbles of ironstone. What seems to have happened here is that a rubbery crust of iron-rich gunge has formed on the bed of the prehistoric river then a strong current has dislodged it and trundled it into an ironstone Swiss roll. Iron is deposited when river water, rich in iron salts, meets brackish water.

deltacoal forestYorkshire was on the equator at the time this rock was laid down 300 million years ago, in a low lying area of lagoons, river deltas and the tropical forests which would form coal.

The surface of the Earth would be lacking in colour if it wasn’t for iron-rich minerals which range through ochre yellows, rusty reds and mineral greens to the fool’s gold of iron pyrites.