By maceration of coal it is possible to extract microfossils that consist of various plant parts. These are briefly described and shown to have stratigraphic value.
Proceedings of the Iowa Academy of Science
©1941 Iowa Academy of Science, Inc.
Wilson, L. R.
"The Occurrence of Plant Microfossils in the Pennsylavanian Coals of the United States (Abstract),"
Proceedings of the Iowa Academy of Science, 48(1), 297-297.
Available at: https://scholarworks.uni.edu/pias/vol48/iss1/72