Gene Wolfe's four-volume epic The Book of the New Sun appears to be set in a far-future version of our world's South America. This is a fact that I only noticed by using my knowledge of fauna, as some of the animals mentioned in the story are only found in South America. I don't remember now which animals these were exactly - maned wolves? brown tapirs? rheas? - but they were distinctive enough and clearly enough described to make me certain of the setting.
Is this geographical setting made clear in any other way in the story text? Other clues set it clearly in the southern hemisphere (I seem to remember the sun is described as being in the north?) but the fauna is the only clue I spotted that specified a continent. Are there other textual clues indicating South America which I missed?
Please clearly mark spoilers from books beyond the first. I read the first book a couple of years ago and didn't get around to continuing the series yet. I'm led to understand that later books will somehow make many things more clear about the setting, but I'm still wondering when and how readers are first meant to realise that the story is set in future South America.