@Tai Chi,
Thank you. Yes, that's an old- probably REALLY old dry stone wall. This stretch of the Mendips between Rodney Stoke and Priddy is just fields and has been fields, divided by these walls and hedges -for years and years and years. The Priddy fair has been held up there since the plague forced people to move it out of the nearby city of Wells in the fourteenth century.
I love it because it's nothing but me and my dog and the wind up there.
This is a little ways away from the snowy road - just a view to show you what it looks like without snow: