I figured that they were amphibian eggs, but I don't know much about such things and wasn't sure. And they could have been any type of amphibian for all I knew. So I took some video and photographs and when I got back I showed them to some of my online pals who are far more knowledgeable abut these things.
The consensus is that they're obviously salamander eggs. But as to the exact species--that's up in the air. It would be nice if they're Hellbenders, which are our largest species of salamander here in the NC mountains. I've never actually seen a Hellbender, and it would be nice to think that I got to see literally hundreds of Hellbender embryos floating in that little pool of water.
Here I am on the exposed rock below the falls. This rock is riddled with many potholes. It was in one such pothole that I saw the clusters of eggs.
Here is a macro shot I took of a single egg. The eggs looked to be absolutely perfect little spheres, and in the center of each sphere was a forming embryo soon to become a baby salamander.
A better view of both masses. Each cluster was about the size of a soccer ball.