• 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 84

More information
  • digital collection
  • archival collection guide
  • transcription tips
 
Saving...
[page]83.[/page] Shell rather large, usually somewhat wider than long; one to two and a half inches wide and three fourths to two inches long. Shape sub-semi-elliptical or trapezoidal, the hinge line forming the axis of the ellips, or the long side of the trapezoid as the case may be; cardinal angles lamellose; hinge line straight. Dorsal valve concave with the most abrupt concavity in front, while it extends backward almost a plane. Near the front there is a slight indication of a mesial ridge; area observed, no beak. Ventral valve extremely convex with the greatest convexity at the umbo; extenuated anteriorly. A mesial sinus extends from near the beak to the anterior margin; beak curved around to hinge line. This valve is
 
Scholarship at Iowa