Ed, at a quarry near my pond in PA, they classify the rocks with designates of "B" and "R"

So you have sizes like "2B" and "2R"

I recently had a load of rock dumped which was the perfect size for riprap. I'll check my receipt and see what classification it was.

The rock I got was sandstone. However, I believe limestone (as Cecil said) is better. I think it can help w/ the Ph.

I'll post some details hopefully later today.

Excerpt from Robert Crais' "The Monkey's Raincoat:"
"She took another microscopic bite of her sandwich, then pushed it away. Maybe she absorbed nutrients from her surroundings."