This would have been before the dinosaurs though as they must have had something to drink in order to sweat (I doubt they had Lucozade vending machines at the time, and so far nobody has unearthed a pair of trousers from a dinosar showing deep enough pockets for loose change
The latest probe to be launched into space
http://news.bbc.co.uk/1/hi/sci/tech/2333323.stm
Is going to do its best to find out just where the water came from and how it actually got into the planets system.
Personally I believe some alien passing our world pulled the chain whilst their flying saucer was stationary (against regulations of course - stickers in the toilet were probably ignored) above one of the poles, probably the South as its bigger, and let loose a large lump of frozen waste effluent, but time will tell