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
One-name study and group it geographically, approximately representing the different family groups. Others attempt to reconstruct lineages. In most one-name studies, a united lineage will not be discovered, but broad perspectives can be achieved, giving clues to name origins and migrations. Many researchers are motivated to go beyond the one-name-study stage and to compile fully researched, single-family histories of some of the families they discover. Accessibility of the data required for a one-name study varies from country to country. Where civil registration indexes are open to public search, they may not be online or gathered in the national capital, but are scattered