New Mexico Museum of Natural History and Science

[Doug Watson]

I don't think there were any hadrosaurs during the Jurassic so I'd guess its a Camptosaurus. I zoomed in as far as I could and it looked like it was falling on a mosasaur while being attacked by some therapod. Old paintings don't really make a lot of sense to me.

I think it is supposed to be having a dustbath. Looks like dust being kicked up around the head and leg. The other animal I think is supposed to be the same species and is just stepping up on the log.  The mosasaur you see is just its left rear leg and its tail. At least that is my best guess.