Well besides the whole geologic column, I'd have to say plate tectonics.
Plate tectonics, which supports the theory of continental drift, is responsible for moving continents and making new ones, creating mountains, for most of the earthquakes and volcanoes around the globe, etc.. There is absolutely no evidence for catastropic plate tectonics, so that is not even a remote possibility.
Evidence:
-- rocks, as well as mineralized and petroleum systems that match up across divides;
-- current movement of the plates (at about a couple cm per year);
-- ocean derived sedimentary rocks at tops of mountains;
-- paleomagnetism;
-- intracontinental island arc and ophiolite remnants;
-- tropical vegetation and fossils in todays artic regions and vice versa;
-- aulocogens;
-- relatively young age of the ocean floor;
--overturned, folded, metamorphosed sedimentary layers.