In 2007, the fossilised skeleton of an Oryctodromeus – a dinosaur around the size of a german shepherd - was found alongside two of its young in a cosy little hole in south-west Montana. The whole lot had become entombed and lain there undisturbed for around 100 million years. They"re part of the Thescelosaurus genus, members of which have also been found at the Colville River site.