• 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 76

More information
  • digital collection
  • archival collection guide
  • transcription tips
 
Saving...
[page]75.[/page] this valve has radial markings and a very prominent cardinal process. Ventral valve flat or slightly concave, or perhaps in some cases slightly convex: beak quite prominent; hinge area moderately wide and striated longitudinally, pedicle opening closed by deltidium. Interior showing prominent dental laminae and a knife-like mesial septum which extends one third to one half the length of valve. Surface marked by radiating costae which increase in number toward the front by the addition of smaller costae between each pair of larger ones; also marked by very fine concentric striae and by lines of growth. Geol. position:-- Upper Carboniferous. Localities:-- Des Moines, Winterset, etc.
 
Scholarship at Iowa