They do look like stones. I love the reflection of the trees and canopy in them. Was there much more moss surrounding them? Maybe a tiny bit more room, but this is pretty terrific. The edges look slightly curled up - looks like gills showing a little.
Ola, what a fine find, and great capture. I too thought it was stones before I opened it up and read your comments. The green moss surrounding them is a very nice plus. It frames them in nicely, and makes them stand out even more so. Very nice.