While ancient walls have been built like yours and still stand, Marcinde's method makes it easier to guarantee that you won't have problems. Your wall looks like it has decent batter, but it cannot be determined from the picture if it's consistent throughout. I think this is one of the most important components of dry-stack retaining wall stability. Keeping batter sufficient throughout will help wall longevity. With greater batter comes greater stability and, personally, I like the look of it as long as it's uniform. You could easily create a wooden triangle with a level attached to gauge the batter uniformly.

Wow, what a project! Not an expert on retaining walls, but I'd probably be googling some of the questions you asked or visiting engineering/landscape forums to see what others might have to say. Best of luck. A link that might be useful: www.paversearch.com/build-retaining-wall-faqs.htm

Stone work is typically somewhat regional in nature.....you don't see a lot of New England type dry stacked stone walls around here because the stone typically used to build these walls is not native. And much of the cost of stone is associated with where it comes from -- be prepared to pay a LOT if you want something that had to be imported, like Connecticut blue stone. Most dry stacked stone walls and certainly those using the smaller, layered stones like you see in New England also have little structural integrity - they are typically used more as ornamental features rather as a retaining wall/slope support or with any kind of soil weight behind it. How tall a wall do you wish to build and what is its purpose? About the only dry stacked walls I've seen around here are the large landscape boulder rock walls or recycled concrete chunks. Of these, only the concrete chunks can be considered a DIY project.

Anyone know of a quarry that sells directly to the public or a dealer in the Los Angeles (or surrounding areas) that wholesales to the public stones/rocks (like fieldstone, basalt, bluestone etc.)? I want to build a short (18" high), dry stacked retaining wall along the back of my property. We have a couple of local places (e.g. Bourget Bros. Building Materials and West LA Building Materials) but they have limited selections and are VERY pricey. Thanks in advance!