Fossil wood and lignite of the Potomac formation
Subtitle: by Frank Hall Knowlton
Contributors: Geological Survey (U.S.)
Series: Bulletin of the United States Geological Survey -- no. 56; Bulletin of the United States Geological Survey -- no. 56.; Mis. doc. (United States. Congress. House) -- 51st Congress, 1st session, no. 244.; United States congressional serial set -- serial no. 2791.
Publisher: Govt. Print. Off.
Published: 1889
Place of publication: Washington
Language: eng
Number of pages: 72
Subjects: Lignite; Paleobotany
Notes: At head of title: United States Geological Survey.

With bulletin no. 55 & 57-61, also issued as House miscellaneous document no. 244 for 51st Congress, 1st session, bound as United States congressional serial set no. 2791.

Includes bibliographical references and index.