Author
Pennsylvania Commission Appointed to Investigate the Bituminous Coal Mines
2
Sisler, James D.
2
Bedford Iron Company (Bedford & Huntingdon Counties, Pa.)
1
Pennsylvania
1
Pennsylvania Inspectors of Mines
1
Pennsylvania. Bureau of Topographic and Geologic Survey
1
Reese, John F.
1
Skema, Viktoras W.
1
Sponseller, Robert D.
1
Whitaker, Wm. J. geologist
1