VandenBygaart, A. J. 2011. Regosolic soils of Canada: Genesis, distribution and classification. Can. J. Soil Sci. 91: 881-887. Regosolic soils of the Canadian System of Soil Classification are those soils that are weakly developed and do not contain a recognizable B horizon at least 5 cm thick. They must be able to support plant life and thus represent the boundary between pedologic and geologic realms. They commonly occur in Canada where recent geomorphic or anthropogenic processes have exposed fresh parent materials to the climatic forcings at the earth's surface, but can also occur where parent materials are highly resistant to weathering or where climatic conditions are arid and cold. A key stage in their development involves stabilization of the parent material usually by vegetation, which through the plant carbon cycle provides organic matter to the surface, a key component of many soil formation processes. Regosolic soils occur broadly across Canada with major areas in southern Quebec, southern Manitoba, the Rocky Mountains and the Arctic. Classification and taxonomy are fairly straightforward in that all Regosolic soils lack a well-developed B horizon. They are divided into two Great Groups based on the development of an Ah horizon that is either greater than 10 cm thick or is less than 10 cm thick or absent.