How Coal Forms and Coal Rank Diagrams
Copyright and Permission
The following diagrams are free to use for educational purposes. These images were created by Stephen Greb, Kentucky Geological Survey, University of Kentucky. Please cite if using in a presentation or publication. We would appreciate it if you could e-mail KGS to inform us of the use of the images. Please contact Rebecca Wang or Stephen Greb at the Survey for permission to use for other purposes.