The largest cache of dinosaur bones ever found has been unearthed in Alberta. From the article: '... officials at the Royal Tyrrell Museum say the Hilda site provides the first solid evidence that some horned dinosaur herds were much larger than previously thought, with numbers comfortably in the high hundreds to low thousands. ... Rather than picturing the animals as drowning while crossing a river, a classic scenario that has been used to explain bonebed occurrences at many sites in Alberta, the research team interpreted the vast coastal landscape as being submerged during tropical storms or hurricanes. With no high ground to escape to, most of the members of the herd drowned in the rising coastal waters. Carcasses were deposited in clumps across kilometers of ancient landscape as floodwaters receded