When I wrote Putting in a pond liner I believe I said something along the lines of 'then you build a drystone wall around the perimeter' with the subscript, 'C'mon it's easy'.
I didn't mean to imply that drystone walling per se was easy, only that laying three or four courses of flat stones against a dirt wall wasn't exactly rocket science. Still, I regret the hubris . Even a pond surround has to be safe to walk on, so consider the following in the nature of an extended P.S..
Drystone walling is a craft of considerable antiquity. It is safe to say that some form of laying stone upon stone without mortar, relying on placement and the force of gravity alone, has been with us since the dawn of time. Nowadays, if you walk into a decently stocked bookstore and look under, say 'gardening ', you are likely to turn up a lavishly illustrated 'How To' book on how to build a drystone wall. You might also find that the wealth of technical data is a bit daunting; what I'd like to do here is provide a short guide to the main principles and practice, and let you the reader take it from there.
First of all, you need a lot of stones, of all shapes and sizes. If you live in the country, a friendly farmer probably has access to an old stone quarry; there are also commercial quarries which will deliver by the truckload. You might even be lucky enough to have an old stone barn or wall which is in ruins and can be mined for stone. In the latter case, take Everything, not just the big squarish bits. You'll see why shortly. How much material you need varies according to how big the wall is to be- as a rough guide, one cubic meter of wall contains approximately one ton of stone.
Second, you need tools; nothing fancy, here, just a spade and what is called in this country a 'lump hammer' which is a small one handed sledge with a handle about ten inches long.
The spade is for digging a footing- just removing a layer of turf about 4-5 inches deep where the wall is to go. The thing to remember here is that no matter the eventual shape of your wall, EVERY blessed stone has to lie level if at all possible. If it goes up hill and down, you dig steps.
The first GREAT PRINCIPLE: A word here about your chief enemy, or principle friend and helper: the law of gravity. Every piece of stone on the face of the earth wants only one thing: to be as close to Earth as possible. A stone on a slanted surface is a stone which will, inevitably, in time, move in the direction of the slant unless prevented. Why spend a lot of time trying to circumvent this- just start off on a level footing.
How wide the base is depends on how high the wall is to be, and here is the second GREAT PRINCIPLE: in dry stone walling every course is laid about the depth of a finger ( about five ml or a quarter inch) further in toward the center of the wall than the course below. Seen in profile, a drystone wall looks like a tall truncated pyramid. You've seen, perhaps, pictures of cottages in the highlands of Scotland with drystone walls? No, you do not have to build a wooden profile and string lines as a guide- useless if you want your wall to curve or be circular in any case. Just use the side of your finger against the edge when you place the stone. This is how you build both sides up without scurrying around the end and down the other side every time a stone goes down across from you. Just feel. It doesn't have to be exact, so long as the wall tapers toward the top.
The third GREAT PRINCIPLE is, every stone you lay should overlap the join between at least two stones on the layer below. Again, study the cottage in http://www.borvemorcottages.co.uk/images/simple_img_4.jpg It doesn't always work out that way but 90 percent of the time it should. Think about it- remember we are using gravity and not mortar.
The fourth GREAT PRINCIPLE is two fold: 1. Every stone placed should lie as level as possible and 2. Every stone laid should neither rock nor move. It works like this: you put the stone in place, it fits well but rocks forward and back or from side to side. This is where all the little bits and shards of stones you've collected come in. Reaching around to the BACK of the stone, you insert what ever you need to keep it stable. NEVER insert a shard from the front, it will almost inevitably work itself loose. Then, when both opposing stones on either side are stable, you use other bits of stone to build a solid, stable center between them. This holds the shards you used to brace the stone in place and makes each and every level of the wall solid enough to walk on. I'm not joking, this is how they test apprentices' work where such skills are taught.
Problems and FAQ: 1:The stone is too big/ too wide/ the wrong shape. Solution: pick another one. However, if it just needs a little bit whacked off, take the lump hammer and hold the stone in the air, against your thigh or put it on SOFT ground. Try to strike it with the edge of the hammer head rather than flat on. Tap sharply rather than wallop. The soft underlay is to damp the vibrations and keep from shattering the whole stone. If it all goes to blazes, don't lose heart. The pieces will still be useful somewhere.
2: I'm at the top, what's next? Solution: hopefully you have some big flat stones left over to make a top course. Otherwise, a bunch of big irregular stones lined up along the top to hold the wall together.
Yes, it's a lot of work. On the plus side it is quiet (except for the bad language) relaxing and intellectually and creatively challenging. Try it sometime. You'll see.