More than 300 papers dealing with stratigraphy and resources studies on coal-bearing rocks in the United States and Canada have been published during the past 9 years. Most of these have been published by the U. S. Geological Survey, the U. S. Bureau of Mines, and the state surveys for Illinois, Indiana, Kansas, Kentucky, Missouri, Ohio, Pennsylvania, and West Virginia. The U. S. Geological Survey has published more than 40 Coal Investigations Maps, which cover 7 and 1/2-minute quadrangles, 15-minute quadrangles, coal fields, or coal districts. Circulars have been published which include the calculation of coal reserves for Colorado, Indiana, Michigan, Montana, New Mexico, Oklahoma, Oregon, North Dakota, South Dakota, Virginia, and Wyoming. The U. S. Bureau of Mines has completed more than 40 county reports which estimate the known recoverable reserves of coking coal in Kentucky, Maryland, Pennsylvania, Tennessee, and West Virginia.