Snippets 8: A non-conformist on the shore

‘Brockram’ and ‘breccia’: the first word suggests something that is solid and long-lasting, the other has a hint of transience, of frippery. But Brockram is a form of breccia; it looks like a congealed and lumpy mess of porridge that has been spilled onto the shore.

It’s a non-conformity, it’s pretending to be older than it is.

We had slithered down a slope of muddy red sandstone, with the ‘protection’ of a knotted rope fixed to an insubstantial metal stake, and had reached the shore of Barrowmouth Bay, a little to the North of St Bees’. Over the centuries, great boulders of the red St Bees’ sandstone have eroded from the high cliffs along this part of the coast, and have tumbled onto the shore. Large and slippery, often coated with green algae, they make progress along the shore difficult but always interesting, because one is forced to stop and look and feel and question the shapes and colours.

Some boulders have drifts of mica embedded in them, hinting that the delicate flakes were swirled by a river’s current into a small depression. Others have marks of ripples, that were formed on the bed of the river delta when the sandy sediments were deposited; still others have swellings or circular indentations, where stones or mud were pressed against the sediments as they were compressed and lithified, and turned to stone. (There is much more about Barrowmouth and St Bees’ sandstone on Solway Shore Stories.)

an anchor

An anchor-stone?

 

I find a bright red stone that is perforated by a hole, the edges of which are scored with grooves. Are they marks worn by ropes, was it perhaps used as an anchor?

 

Most of the boulders are the New Red sandstone but they are tumbled upon rock from a much older age, a sandstone that is darker, purplish, in colour; there are patches too of a paler yellow-green variant. This is Carboniferous, ‘Coal-Measures’, sandstone within which the West Cumbrian coal-fields are embedded.

Finally we reach the rock that is an intruder. Even though the Brockram looks artificial and unattractive, out of place both aesthetically and geologically, it’s a special thing to see. It caps wave-washed boulders; it has spilled into crevices, and forms a smooth-topped platform over the sandstone; it is lumpy with gravel and pebbles.

This ‘non-conformity’ and the way it arose is extraordinary. The surface of the Coal Measures sandstone had been smoothed and hollowed, slowly eroded as it was exposed and oxidised in the desert air – and then suddenly, into every dip and joint had poured this mess of Brockram, forming a dramatic contrast of colour and texture. In the Permo-Trias a river torrent had flashed out onto the sandstone, its powerful currents carrying a mixture of volcanic material, limestones, sandstone and even Ennerdale granite from the ‘Lake District’ region (which was then at about the latitude of the current Sahara desert), and had deposited this breccia in a fan.

It does not ‘conform’ because there is a gap in the geological record between the old sandstone and the younger breccia – the rock from the top of the Coal Measure sandstone had been eroded and removed.

We sit on the rocks and drink coffee, watching the sea, hearing the regular thump-thump-thump of an engine, a trawler unseen in the fog, heading West to the Irish Sea. Two oyster-catchers fly low over the water’s quiet surface, their wing-tips almost touching their mirrored reflections. A seal watches us and, unimpressed, sinks down into the water and disappears.

The tide is coming in and eventually, we leave this out-of-the-way and unusual place, to scramble back along the shore, haul ourselves up the rope, and climb the long steep path to the top of the cliff.

Advertisements
This entry was posted in quarries, sandstone, Snippets and tagged , , , , , , . Bookmark the permalink.