Paleogeography in a broad way controls the deposition and distribution of source beds and reservoirs. The search for new deposits of petroleum is aided by the use of special paleogeographic maps. The term eulithogeography is introduced to cover distribution of favorable lithologic areas. Other types of maps that may be used show salinity, thickness of sands, paleogeology and paleotopography. All of these maps can be combined with structural contour maps to show depositional and post-depositional dips.