• Transcribe
  • Translate

Coal Measures and Coal Mining in Iowa, including paleontology and a discussion on the coal formation; also the methods of mining by Russell T. Hartman, 1898

Coal Measures and Coal Mining in Iowa by Russell T. Hartman, 1898, Page 180

More information
  • digital collection
  • archival collection guide
  • transcription tips
 
Saving...
[page]179.[/page] be seen at the surface. They are the beds of our modern streams. The effects of preglacial erosion cannot be seen at the surface. These old water courses, now filled with sand, gravel, and clay, often intermingled with the trunks and roots of trees, are frequently and unexpectedly encountered in the mines of Iowa. Preglacial channels vary in width and depth the same as our modern water courses. Some of them merely cut out the overlying strata thereby greatly weakening the roof, often causing it to fall. Others cut out the coal and down to or even to quite a great depth into the bedrock. In width these channels are known to vary from a few feet to nearly a mile. When such a channel, filled with sand or gravel, is encountered the work
 
Scholarship at Iowa