Joe,
Thank you for your kind words. Yes, we do get hours of enjoyment out of the pond and the pump house, too!
In answer to your question, all the rock is limestone and, yes, it is dry stacked or dry laid as some call it. Limestone is primarily what you find in central Kentucky. One end of the lower pond is surrounded by sandstone, which I brought from my home county up in the mountains of eastern Kentucky. I wanted to have something from where I grew up in the stonework, so that is why you see the large, flat brown rock in one of Jen's pictures of the lower pond looking up at the upper pond.
I left my camera home when we went around on the pond tour. Jen took hers and has promised to post some back here. Maybe when she gets through grading papers this evening she will do just that!
Dale