Continental drift is created at spreading centers, and this, along with subduction, drives the system of plates in a chaotic manner, resulting in continuous orogeny and areas of isostatic imbalance. The theory of plate tectonics explains all this, including the movement of the continents, better than Wegener's theory. Hans Stille and Leopold Kober opposed the idea of continental drift and worked on a "fixist" geosyncline model with Earth contraction playing a key role in the formation of orogens. Other geologists who opposed continental drift were Bailey Willis, Charles Schuchert, Rollin Chamberlin and Walther Bucher. In 1939 an international geological conference was held
Ice Age: Continental Drift accompanied by the short animated film "The Longest Daycare" featuring Maggie Simpson. As a promotion for "Ice Age: Continental Drift", Fox released two 3-minute short segments from the film, titled "Scrat's Continental Crack-up" and "Scrat's Continental Crack-up: Part 2". The first part premiered as a theatrical release attached to "Gulliver's Travels" in 2010, and it was released on-line on January 6, 2011, on iTunes Movie Trailers. The second part was released on November 16, 2011, on iTunes, and debuted in theatres with "". The first part shows how the Scrat's actions lead to split of the continents, while in the