St Abbs sits on the right shoulder of Britain, just below where the landmass tapers to a narrow neck and is topped by the head, which is the bulk of Scotland. It is a headland of high cliffs. In the summer, the precipices host colonies of breeding kittiwakes, guillemots and razorbills. For this painting, I was sitting high up on cliff tops at St Abbs, looking northwest to where land curves round out of sight to the nuclear power station and Dunbar, on to the mouth of the Firth of Forth and then to Edinburgh.
One evening last week, I walked 20 yards off road to Pettico Wick, a small bay at the north east of the headland. Suddenly, a story jumped out at me, a narrative of lifeless depths and sudden fiery violence.
This is the first drawing I did, as usual using pen and ink and water on the fairly resistant paper in the Moleskine sketchbook. It has been adjusted using the “glow” filter on the photoshop app.
What I tried to show is the bay and sea, with a jetty stretching from land to slide beneath the water. To my left are the regular layers of sedimentary rocks sloping down into the sea. These are formed of compacted silt, mud or of greywacke, a term for irregularly sized mineral granules set in a fine clay-like matrix. These rocks fracture with simple percussion. In front, only a hundred yards away are sea stacks formed of amorphous dysplastic lavas, the same stuff that forms the right hand cliffs. These rocks are much harder and resist the limited force I can bring to bear.
The original sketch is below.
It was obvious that in this small bay, I sat on a boundary marking ancient cataclysms.
I now know that the rocks on my left were laid down in very deep seas about 430 million years ago. This is before our ancestral line could be dignified by the term fish. The greywacke rock comprising mixed size rock grains is apparently formed from submarine avalanches and turbidity in the deep water of oceanic trenches or at the edges of continental shelves. Some 15 to 30 million years later, volcanic eruption sent lava flowing in various directions. This was at a time when fish had radiated and come to dominate the seas. The relative resistance of these hard rocks has created the headland to my right.