Been to Siccar Point - as a geologist I'd say there probably are lots more undiscovered (or more likely - not discovered by the right person) things in a science like geology, because it is hard to replicate things that change over such massive timescales. <br>The asteroid mass-extinction events were really only backed up with proofs in the 90's (computerised mapping). Only 3 weeks ago the volcano in the Pacific went off with a explosion many multiples of times higher than anticipated. Some animals seemingly can tell that an earthquake is about to happen, but there's nothing humans have spotted on their scientific instruments etc....theres more out there - and a lot of it will be obvious with time.