I love this wall! There are over 5000 miles of dry stone walls in the Yorkshire Dales, one of the Yorkshire Dales' most distinctive features, and are some of the oldest man-made landscape features.
The very first dry stone walls were probably created centuries ago when early farmers were clearing the land for cultivation. Some walls are really thicker than might seem necessary, just because they were built in very stony areas. Most walls are built to mark field boundaries or mark land ownership, and limit movement by sheep and cows.
Tom Lord of Lower Winskill Farm, Langcliffe has over seven miles of dry stone walls on his farm, some of which date back to the 13th century and are believed to have been built to deter wolves! When on a tour of his farm farm in Wensleydale, Adrian Thornton-Berry showed me some very straight walls rising up the hill near Swinithwaite and said they were built around 200 years ago by French prisoners of war taken from Napoleaon's army. Nearby are some large block foundations to a wall that dates back to the times of the Knights Templar. There's plenty of hidden history in those miles and miles of walls!
If you see very large stones being used as the base of the wall, that's often an indication of a wall that may date back to medieval times. Straight walls and fields that seem more uniform may date back from the enclosures period of the late 18th and early 19th century.
Dry stone walls are 'dry' because they are made without mortar, simply relying on their complex structure to stay up. The foundation course usually consists of larger stones, upon which two wall faces are built, forming a cavity which is filled will smaller stones. Walls are finished or capped with large stones laid at an angle or on edge. Through stones bind the two wall faces together. If you look at walls in different parts of the Dales, you'll notice small differences in their construction. If you compare the Dales dry stone walls to those in Devon and Cornwall and you'll notice a very different style.