An idea I'm pursuing is the boundary between human-made and natural features in the landscape. The imprint of human activity goes back as long as there have been humans, I suppose. In the British Isles, any traces prior to about 12,000 years ago have been erased by the last glacial period, but that still leaves quite a stretch of time, in which many layers have been superimposed on the raw gravel, sand and silt debris of glaciation. The plants that colonised the newly-accessible wilderness were followed by animals, and the animals were followed by people in search of game at this edge of the habitable world.
About halfway through this 12,000-year-old story the people began farming, in patches, and with setbacks due to climatic cycles. It took millennia for settlements to emerge that were any more than hamlets, and field systems to become more widespread.
I don't know how far back these field systems near Malham go. What attracted me when I took this photo was not just the pleasing pattern, but the uncertainty about what's natural and what man-made. The little strip-fields – lynchets – merge into terraces caused by the river's erosion and deposition in the valley. The contours are emphasised by the fish-net tracery of dry-stone walls, and the patches of woodland on any slopes too steep to cultivate.