It's been a rather warm and rainy Summer around here, and I'm seeing some Black Goo growing in my creek rock driveway. Doing some research, it appears to be something called "Nostoc Algae". It is black, shiny, and rather gooey, and looks nasty. Has anyone had this growth in their driveway, and know of some commercially available "herbicide" that might kill it off? There is info on the Internet that talks about a couple of chemicals that can kill it, but no Brand names. I may pick up some Roundup the next time I go to the store, and try that, but if anyone has had this issue, and found a way to kill it off, I would be Very Interested.