DIY History | Transcribe | Scholarship at Iowa | 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 101

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 101

[page]100.[/page]

Geol. Survey west of 100th Meridian, Vol. IV.
     Shell small, form rather variable, generally sub-trigonal, usually somewhat wider than long, gibbous, front sinuous.
     Dorsal valve convex, greatest convexity at or slightly posterior to middle; mesial fold prominent, extending from umbo to anterior margin, composed of three, rarely more, plications; sides curve rather abruptly from fold to each side; three or four plications each side of fold; beak incurved.
     Ventral valve not quite so convex as other valve; mesial sinus from umbo to front, occupied by two, rarely more, plications; three or four plications each side of sinus; beak prominent projecting beyond beak of other valve; foramen in beak; no hinge area.
Geol. Pos. Missouri stage, Upper Carboniferous.
Localities, Montgomery County, Iowa; and in

Saving...

[page]100.[/page] Geol. Survey west of 100th Meridian, Vol. IV. Shell small, form rather variable, generally sub-trigonal, usually somewhat wider than long, gibbous, front sinuous. Dorsal valve convex, greatest convexity at or slightly posterior to middle; mesial fold prominent, extending from umbo to anterior margin, composed of three, rarely more, plications; sides curve rather abruptly from fold to each side; three or four plications each side of fold; beak incurved. Ventral valve not quite so convex as other valve; mesial sinus from umbo to front, occupied by two, rarely more, plications; three or four plications each side of sinus; beak prominent projecting beyond beak of other valve; foramen in beak; no hinge area. Geol. Pos. Missouri stage, Upper Carboniferous. Localities, Montgomery County, Iowa; and in