Hi all, jb) Everything from Zebra mussels (dumped in Lake Erie) to just plain junk has been used to ballast ships. But perhaps the most interesting are the whispering sands of Lake Michigan. There are (at least) two Lake Michigan beaches on the southern shores of the Upper Peninsula that have a rare sand, in that they "whisper" as you walk across them. I have not researched this phenomenon world wide, but I know there are such sands in the Queen's Chamber of the Great Pyramid. I know of a cache of the "whispering" Pyramid sand in the UK, so when I go to Michigan this Summer I'll get some of the Michigan variety and have it compared. jb