Ornithopods were some of the most common dinosaurs unearthed in the 19th century, mainly because so many of them lived in Europe (where paleontology was pretty much invented back in the 18th and 19th centuries). Discovered in 1869, Rhabdodon has yet to be properly classified, since (not to get too technical) it shares some of the characteristics of two types of ornithopods: iguanodonts (herbivorous dinosaurs similar in size and build) and hypsilophodonts. Rhabdodon was a fairly small ornithopod for its time and place; its most notable features were its roundish teeth and its unusually blunt head. You are looking for a bison on a unique host in a thick large oak clump.