Robuta

https://www.psu.edu/news/academics/story/new-book-examines-pennsylvania-coal-and-coke-communities-detail
The Coal and Coke Heritage Center at Penn State Fayette has just published a book by John A. Enman that examines Pennsylvania coal and coke communities in such...
pennsylvania coalnewbookexaminescoke
https://www.usgs.gov/publications/stratigraphic-cross-sections-within-homer-city-pennsylvania-dedicated-coal-reserve
No abstract available.
cross sectionsthe homerstratigraphicwithincity