Posted: 30/08/2013 at 16:04
Three foot is way more than is normal for field boundaries. If there is a good batter on the walls the base would be much more than 3 ft wide.
If I remember the roads agency had a frame which they filled with soil and then faced the banks with turf and planted on top.
Remember plants will grow and will be far cheaper than a high double stone wall.
May I suggest a little research on the internet. Different counties have different traditional field boundaries and banks.