Between 1999 and 2007, the U.S. Geological Survey (USGS) investigated coalbed methane (CBM) resources in the Wyoming portion of the Powder River Basin (PRB) (fig. 1). The study also included the CBM resources in the North Dakota portion of the Williston Basin (WB) of North Dakota and the Wyoming portion of the Green River Basin (GRB) of Wyoming
(fig. 1). This project involved the cooperation of the State Office, Reservoir Management Group (RMG) of the Bureau of Land Management (BLM) in Casper, Wyo., and 16 independent gas operators in the Powder River, Williston, and Green River Basins. The USGS and BLM entered into agreements with these CBM operators to supply samples for the USGS to analyze and provide the RMG with rapid, timely results of total gas desorbed, coal quality, and high-pressure methane adsorption isotherm data (Stricker and others, 2006, 2007). This program resulted in the collection of 963 cored coal samples (also called canister samples,
or simply canisters, in this report) from 37 core holes (also called wells in this report; fig. 1, table 1). This report presents megascopic lithologic descriptive data collected from canister samples extracted from the 37 wells cored for this project.