Pennsylvania Geology Available as a PDF
There is a growing list of great mineral PDF files on the web. Here is the latest I found: From PA Dept of Natural Resources. Please see Pennsylvania Geology for…
There is a growing list of great mineral PDF files on the web. Here is the latest I found: From PA Dept of Natural Resources. Please see Pennsylvania Geology for…
Report of the Geological Survey of OhioDr. J. S. Newberry, State Geologist (volumes 1-4)Dr. Edward Orton, State Geologist (volumes 5-11) Published by authority of the Legislature of OhioColumbus, Ohio :…