Beckles Footprints - Iguanodon stands up
In 1854 Samuel Beckles reported finding a number of three-toed footprints in the Weald formation of the Isle of Wight. They looked like bird tracks, but Beckles did not rule out the possibility that they may be those of dinosaurs.
Beckles later found the hind limb of a young Iguanodon on the Isle of Wight, and showed it to Richard Owen. The bones were three-toed and the same size as the previously discovered footprints.
"On the ornithoidichnites of the Wealden" Quarterly Journal of the Geological Society of London, vol 10 (1854) pp 456-464. S.H.Beckles
In 1858 Owen connected the limb with the footprints, in Monograph on the Fossil Reptilia of the Wealden Formation Part IV. No longer could we assume that three-toed footprints belonged to birds.
This step provided Thomas Huxley, who had already argued in Darwinian fashion that birds and dinosaurs came from common stock, with the evidence that he needed. In 1868 he argued that Iguanodon had sufficiently strong hind limbs and feet to support itself on its hind legs - it was a bipedal dinosaur.
"On the Animals which are most nearly intermediate between Birds and the Reptiles," in Annals and Magazine of Natural History, series 4, vol. 2 (1868), pp.66-75 Thomas Henry Huxley.