The Highland Boundary Fault runs across the width of Scotland from Arran in the south-west to outside Stonehaven on the north-east coast. Around Angus it’s quite a wide zone with a mile between sandstone (lowland) and psammite/pelite (characteristic of the highlands), containing other rock types such as slate, serpentinite and igneous influences. The fields below this photo are pyroclastic igneous tuff (ignimbrite). The water to the east is Loch Lintrathen. There’s half a 22º solar halo to the west.