The layer represents Oil and Natural Gas Fields. Generally, Oil and Natural Gas “Fields” are defined as “a low in the Earth’s crust of tectonic origin in which sediments have accumulated.” This definition was originally defined by the Bureau of Land Management (BLM). Within the larger area of the basins this feature class also contains smaller geographic “plays” which are defined as “A set of known or postulated oil and gas accumulations sharing similar geologic, geographic, and temporal properties, such as source rock, migration, pathway, timing, trapping mechanism, and hydrocarbon type. A play differs from a basin; a basin can include one or more plays.” This definition was originally defined by the United States Geologic Survey (USGS) and was appropriated for use in the creation of this feature class. The geographic coverage of this layer is the Continental United States, Canada, and Mexico.