There is a very large resource of natural gas known to exist in Tight Sands in the U.S.A. Most of these formations have been identified in geologic basins west of the Mississippi river. Some gas sands ion eastern basins may in due course, be placed in this category. Gas resources found in the Devonian Shale in Appalachia and other eastern basins have been placed in a separate category. However, both Tight Sands and Devonian Shales resources require major advances in technology before large scale commercial development will l take place.