Swimming Ankylosaurs?

The Theory behind Ankylosaurs possessing aquatic abilities is sprouted from the large amount of Ankylosaur remains found in rocks formed in marine environments. Examples off such specimens include the famous Suncor Ankylosaur. The Suncor Ankylosaur was accidentally stumbled upon by workers at Suncor's millennium mine in Alberta, Canada. Immediately Palaeontologists from the Royal Tyrell Museum rushed to scene. Initially they believed it was a Marine Reptile but later realized they were looking at a Ankylosaur. Other remains include Skeletal components from the Gault clay of Folkestone, UK and from the Cambridge Greensand. Other remains have been found in the chalk of England and Kansas. So why so Ankylosaurs appear so prolifically in marine deposits. Is it down to the fact that their bodies merely floated out to sea after their death. Or does this represent a semi-aquatic lifestyle? A semi aquatic lifestyle would mean that Ankylosaurs would have lived in the same way as a Hippo their body shape does seem similar. Both have short squat legs and bulky bodies. So superficially Ankylosaurs share features with modern semi-aquatic herbivores. But what would the benefits of a semi-aquatic lifestyle be? It is a useful advantage in terms of escaping predators that are not as skilled at swimming or cannot swim at all. Additionally herbivores can exploit nutrient rich aquatic plants (first suggested for Ankylosaurs by Mehl in 1936). Ankylosaurs would have been very heavy due to their armour and therefore speed would not have been on their side, thus if they were semi-aquatic escaping into water would have aided their escape. Another comparison with a Hippo is that they are slow and sluggish on the ground but graceful and fairly fast in the water. But how could a creature weighing several tonnes support itself and move through the water. There are many theories behind how Ankylosaurs could achieve buoyancy. An interesting theory is gas. As a large herbivore an Ankylosaur would have produced plenty of gas as a result of the digestion of plants. The theory states that this gas could have been used to achieve buoyancy in water as the Dinosaurs bowels would have contained plenty of stinky methane. No matter how elaborate the theories may be leading experts on Ankylosaurs argue otherwise. Walter Coombs a leading authority on Ankylosaurs doubts whether they were aquatic 'These 'Marine Nodosaurids' have very close relatives that lived far in land, and lack features that make them any better adapted for water than their inland cousins'. Despite this opinion many still support the idea of aquatic Ankylosaurs. So semi-aquatic grazers or drifting corpses? You decide.