Can an american history teacher give tests over Geography subjects without having us study then?

OK here is the thing, our teacher was in a bad mood and told us by tomorrow we had to learn every country's capital by the Rio Grand all the way to Magellan Straight or something like that (about 20-25 i don't know exact number). i'm in his AMERICAN history cl that the capitols of mexico and stuff are nothing to do with the presidency of Taft and so we had nothing on them in our texts. anyways i was just wondering if this is aloud or if there is some law agents it? i dont think we should suffer for him being in a bad mood