This one here, we have no idea what it is - it's a great example of a Pipestone Creek mystery." Kevin Church/BBC News Prof Bamforth's dog, Aster, on lookout dutiesThe bones all belong to a dinosaur called Pachyrhinosaurus. Walking with Dinosaurs/BBC Studios Pachyrhinosaurus had distinctive unicorn-style horns, as shown in this computer-generated imageBigger beasts offering cluesAnd this patch of north-western Alberta wasn't just home to Pachyrhinosaurus. He is currently working on a huge Pachyrhinosaurus skull that's about 1.5m long and has been nicknamed "Big Sam". The new series of Walking With Dinosaurs starts on Sunday 25 May at 18:25 BST on BBC One, with all episodes available on BBC iPlayer.