The surficial geology map of the Island of Montreal is an image that identifies the nature of the soils by their lithology and origin. The legend identifies each soil type by a different color, summarizing its composition (e.g. sand, clay, silt or silt), in addition to its origin or mode of deposition (e.g. glacial till, marine or fluvial deposit). It is taken from a publication of the Geological Survey of Canada. This publication deals not only with the identification but also with the properties of "surficial deposits". In geology, the term " surficial deposits" refers to all unconsolidated soils, as opposed to rocks or "consolidated formations".