On the Origin of Species of finding their "centre of creation". The three Fuegian missionaries the expedition returned to Tierra del Fuego were friendly and civilised, yet to Darwin their relatives on the island seemed "miserable, degraded savages", and he no longer saw an unbridgeable gap between humans and animals. As the "Beagle" neared England in 1836, he noted that species might not be fixed. Richard Owen showed that fossils of extinct species Darwin found in South America were allied to living species on the same continent. In March 1837, ornithologist John Gould announced that Darwin's rhea was a separate species from the previously described
Reactions to On the Origin of Species example and Ramsay's data in chapter 9 of "On the Origin of Species" to estimate that erosion of the Weald's layered dome of Lower Cretaceous rocks “must have required 306,662,400 years; or say three hundred million years“. The "necessary corrections" Darwin made to his drafts for the second edition of the "Origin" were based on comments from others, particularly Lyell, and added a caveat suggesting a faster rate of erosion of the Weald: "perhaps it would be safer to allow two or three inches per century, and this would reduce the number of years to one hundred and fifty or